Is xanthan gum bad for you?

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Xanthan gum is a common food used to thicken and stabilize a wide range of products. It is derived from the fermentation of carbohydrates by the Xanthomonas campestris bacterium. While it is generally considered safe for consumption, some concerns have been raised about its potential effects on health.

Xanthan gum has several beneficial properties. It improves the texture and consistency of food products, preventing them from separating and maintaining a desirable mouthfeel. Additionally, it is effective in gluten-free baking as it helps to mimic the elasticity and structure typically provided by gluten.

Research suggests that xanthan gum is well-tolerated by most people. However, some individuals may experience digestive issues such as bloating, gas, or diarrhea when consuming large amounts. This is because xanthan gum is a soluble fiber that can ferment in the gut, leading to these discomforts. It is important to note that such reactions are rare and usually occur only in sensitive individuals or when consumed in excessive quantities.

As with any food additive, it is advisable to consume xanthan gum in moderation. The Acceptable Daily Intake (ADI) set by regulatory authorities ensures that the amount of xanthan gum used in food products remains well within

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Skincare enthusiasts are constantly exploring new combinations of ingredients to enhance their skincare routines. Two popular ingredients that have gained significant attention in recent years are copper peptides and retinol. Copper peptides are known for their skin rejuvenating properties, while retinol is hailed as a powerful anti-aging ingredient. In this blog, we will delve into the topic and explore whether or not it is safe and effective to use copper peptides with retinol.

Copper peptides are naturally occurring compounds that consist of copper ions bonded with small protein fragments called peptides. They are valued for their ability to stimulate collagen production, promote wound healing, and increase skin elasticity. Copper peptides work by penetrating the skin and activating various cellular processes that contribute to skin rejuvenation.

Retinol, on the other hand, is a derivative of vitamin A and a well-known ingredient in the realm of skincare. It boasts multiple benefits, including stimulating collagen production, reducing the appearance of wrinkles and fine lines, improving skin texture, and promoting cellular turnover. Retinol works by increasing the rate at which skin cells turnover, revealing newer and healthier skin cells.

The decision to use copper peptides with retinol ultimately depends on your skin's individual tolerance and needs. While some individuals may find success in incorporating these ingredients into their skincare routines, others may experience adverse reactions. It is essential to listen to your skin and make adjustments accordingly.

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On the impact that water has on waterborne polyurethane, we can delve into it from two perspectives. Firstly, water can penetrate between the molecules of waterborne polyurethane, resin and this effect is similar to that of a plasticizer. In this process, water undergoes hydrogen bonding interactions with the polar carbamate groups in the polyurethane molecules, resulting in a significant reduction in the hydrogen bonding effects between the main chains of the original polymer, thereby causing a notable decline in the physical properties of the waterborne polyurethane resin. However, this phenomenon of water absorption is reversible, that is, it belongs to the category of physical changes. When we treat the waterborne polyurethane resin through drying and dehydration, its properties can be effectively restored.

On the other hand, there is also a chemical change between water and waterborne polyurethane, which is irreversible. In the various types of hydrolysis processes of waterborne polyurethane, the hydrolysis phenomenon of polyester polyurethane is particularly evident. Specifically, when the ester groups in the main chain of the polyester polyurethane undergo hydrolysis, two shorter chains are generated, one of which has a hydroxyl end, while the other has a carboxyl end. It is worth noting that this carboxyl has an acidic property, which can further promote the hydrolysis of other ester chain links, forming a self-catalytic chain reaction. In addition, some alkaline substances, such as urea and ammonia types, as well as catalysts used in the preparation of waterborne polyurethane, such as dibutyl tin dilaurate and stannous octanoate, if they remain in the polyurethane system, can also serve as catalysts for hydrolysis.

Water based polyurethane resin manufacturer

The hydrolysis process of waterborne polyurethane resin also varies depending on the type. Since the ester groups in polyester polyurethane are prone to hydrolysis, the hydrolysis effect mainly manifests as the breakage of the main chain, resulting in a significant reduction in the molecular weight, a sharp decline in tensile strength, and elongation. However, for polyether polyurethane, due to the good hydrolysis resistance of the ether groups and the carbamate groups, its hydrolysis effect is manifested as the gradual breakdown of the crosslinking, with the molecular weight gradually decreasing, and the tensile strength decreasing relatively slowly, while the elongation initially increases and then decreases.

In terms of anti-hydrolysis ability, there are obvious differences between the groups of waterborne polyurethane. Generally speaking, the anti-hydrolysis ability of the ether group is stronger, followed by the carbamate group, then the ureas and bis-ureas, while the anti-hydrolysis ability of the ester group is relatively weak. It is worth mentioning that the hydrolysis stability of polyether polyurethane is usually about 5 to 10 times that of polyester type. In order to improve the hydrolysis stability of polyester polyurethane, researchers typically adopt methods such as reducing the acid value of the polyester, adding anti-hydrolysis aids, or changing the structure of the polyurethane soft block chain link. The search for test data shows that when preparing polyester polyurethane, if the number of methylene groups in the used diol is larger, the resulting polyurethane's hydrolysis stability will also be correspondingly increased.

To select the suitable polyurethane resin for gravure lamination ink, the following several key factors need to be considered:

Printing substrate: Determine the type of substrate on which the ink will be applied, such as paper, plastic film, etc. Different substrates may require polyurethane resin with specific properties. Adhesion: Ensure that the polyurethane resin can provide good adhesion on the substrate to prevent the ink from peeling off. Solvent resistance: Select the polyurethane resin with sufficient solvent resistance according to the type of solvent the ink comes into contact with. Elasticity and toughness: Consider the bending, folding, or stretching that the printed matter may undergo, and select the resin with appropriate elasticity and toughness. Drying speed: Select the polyurethane resin with a drying speed that meets the requirements according to the production efficiency requirements. Weather resistance: If the printed matter needs to be exposed in the outdoor environment, select the resin with good weather resistance. Chemical stability: Ensure that the polyurethane resin can tolerate the chemicals that may be encountered in the printing process. Viscosity and fluidity: Select the resin with suitable viscosity and fluidity according to the requirements of the printing equipment and process. Compatibility: Be compatible with other ink components and additives to avoid adverse reactions. Cost: Consider cost factors on the premise of meeting performance requirements. Supplier reputation: Select reliable suppliers to ensure product quality and technical support. Technical data and test reports: Refer to the technical data and related test reports provided by the supplier to understand the performance characteristics of the resin. Sample test: Conduct sample tests under actual printing conditions to assess whether the performance of the polyurethane resin meets the requirements.

Polyurethane resin is a type of polymer that can function as a binder in film printing inks. Here's how it contributes to the performance of the ink in a film printing application:

1. Adhesion: Polyurethane resin are known for their excellent adhesion properties, which allows the ink to strongly adhere to various film substrates such as polyethylene (PE), polypropylene (PP), and other plastic films. This ensures that the printed design remains intact and durable, even under stress or exposure to different environmental conditions.

2. Flexibility: Polyurethane binder offer high flexibility, which is crucial for printing on flexible films. The ink must be able to withstand bending and stretching without cracking or peeling, and polyurethane resins provide this necessary elasticity.

3. Abrasion Resistance: In packaging and other applications where the printed film may be handled frequently, the ink needs to withstand abrasion. Polyurethane resins can enhance the abrasion resistance of the ink, preserving the quality of the printed image or text.

4. Chemical Resistance: Polyurethane resins often exhibit good resistance to chemicals, including solvents and other substances that the packaged goods may come into contact with. This feature is important for maintaining the integrity of the printed image and ensuring that the ink does not degrade due to chemical exposure.

5. UV Resistance: Polyurethane resins can also provide ultraviolet (UV) light resistance, which is essential for products that will be exposed to sunlight or UV radiation. This helps prevent color fading and ensures the long-term vibrancy of the printed design.

6. Weatherability: Similar to UV resistance, polyurethane resins can improve the weatherability of the ink, making it suitable for outdoor use or for applications where the printed film may be exposed to varying weather conditions.

7. Printability: Polyurethane resins can contribute to the overall printability of the ink by ensuring good wetting and leveling on the film surface, resulting in a uniform and clear print.

8. Compatibility: They are often designed to be compatible with other components of the ink formulation, such as solvents, pigments, and additives, allowing for the creation of a stable ink system with the desired properties.

In summary, polyurethane resins used as binders ins film printing ink provide strong adhesion, flexibility, abrasion resistance, chemical resistance, UV resistance, weatherability, printability, and compatibility, all of which are crucial for producing high-quality printed films that meet the specific demands of the application.

Polyacrylamide (PAM) is a versatile polymer that finds applications in various industries, including coal washing. Coal washing is a process used to remove impurities from coal before it is burned for energy production. Polyacrylamide can be applied in coal washing for several purposes. Here are some common applications:

1. Solid-liquid separation: Polyacrylamide is used as a flocculant in the coal washing process to promote solid-liquid separation. It helps in agglomerating fine coal particles and settling them faster, resulting in improved solid-liquid separation efficiency. By forming larger and denser flocs, polyacrylamide aids in the sedimentation of coal particles, leading to cleaner coal and reduced water consumption.

2. Filtration aids: Polyacrylamide can act as a filtration aid in coal washing. It enhances the cake formation on filter media, improves filtration rates, and reduces moisture content in the final coal product. By facilitating the dewatering process, polyacrylamide helps in reducing the moisture content of coal, which improves its combustion efficiency.

3. Foam control: During the coal washing process, foaming can occur, which interferes with the separation and dewatering steps. Polyacrylamide can be used as an antifoaming agent to suppress foam formation and enhance the efficiency of the coal washing process.

4. Rheology modification: Polyacrylamide can modify the rheology (flow properties) of the coal washing slurry. By adjusting the viscosity and consistency of the slurry, it helps in controlling the flow rate, improving mixing efficiency, and reducing sedimentation and settling time.

It's worth noting that the specific application and dosage of polyacrylamide in coal washing may vary depending on the coal characteristics, washing process, and plant conditions. The selection of the appropriate molecular weight and charge characteristics of polyacrylamide is crucial to achieve desired results in coal washing operations. Additionally, it's important to handle and use polyacrylamide in accordance with safety guidelines and environmental regulations to minimize any potential risks associated with its use.

The liquid part of the ink component is called the binder; the solid component is the color material (pigment or dye); and various additives.The connecting material is a colloidal fluid with a certain viscosity. Its function is first to serve as a carrier for pigments, mixing and connecting solid particles such as powdered pigments. The pigments are evenly dispersed in it, relying on its wetting effect. , it is easier to be ground finely on the grinding machine; secondly, it serves as a binder to enable the pigment to be finally fixed on the surface of the substrate to achieve the purpose of displaying text, images, marks, decoration, etc.It is also relying on its adhesion function that the ink can be transferred and delivered on the printing press.Finally, on the printed matter, the connecting material also plays the role of a protective film, presents the necessary gloss, and can even protect the substrate.

The quality of the connecting material directly affects the performance of the ink, because the connecting material determines the viscosity, stickiness, dryness, fluidity and other properties of the ink to a large extent.If you want to get high-quality ink, you must use high-quality connecting materials.The various properties of the ink binder determine the various adaptability of the printing ink. The resins used in plastic gravure printing inks generally include chlorinated polypropylene, polyamide, polyurethane, etc.For a long time, chlorinated polypropylene has occupied most of the resin market for gravure composite back printing inks due to its low price and excellent adhesion to OPP. However, its biggest shortcoming is that its main solvent is toluene, and environmentally friendly solvents such as ester are usually used. Alcohol-based solvents are ineffective. Solvent-based polyurethane binder for ink has the advantages of easy use, stable performance, strong adhesion, excellent gloss, and good heat resistance. It can meet the requirements of various printing methods, especially suitable for screen printing, plastic packaging, and composite films. aspect.Industrialization has been achieved in foreign countries in the 1970s, such as Toyo Corporation of Japan, Dainippon Ink Chemical Industries, and Takeda Pharmaceuticals. The polyurethane ink connecting materials used in China are generally polyurethane rubber particles imported from abroad, and then processed and used. The demand reaches 30,000 tons.In recent years, many domestic production and scientific research units have been engaged in the research of polyurethane ink connectors, and have achieved good results. For example, units that can withstand 121°C and 135°C cooking ink connectors have been put into production and are widely promoted and used in the market. , but there is a certain gap between the comprehensive performance of the product and imported products. Improving the comprehensive performance of the product and developing multi-functional products are the focus of domestic research on polyurethane ink connecting materials.

The polyurethane resin used in ink is generally formed by the reaction of polyester/polyether polyol and isocyanate, with a molecular force of about 20,000 to 40,000.The solvents are mainly benzene, ketone and ester solvents.During the research and development process, ketone ester solvents or alcohol ester solvents can be used to prepare corresponding benzene-free ink resins according to the environmental protection needs of ink factories and printing factories.

Characteristics of polyurethane resin for ink

1. Excellent yellowing resistance

Polyurethane resin for ink is mainly synthesized from aliphatic polyester and aliphatic isocyanate as the main raw materials during the preparation process. It has excellent optical stability compared to aromatic polyurethane, and the film has excellent yellowing resistance after film formation.

2. Excellent adhesion fastness to film substrates

The molecular segments of polyurethane resin for ink contain polar groups such as urethane, allophanate, ester bond, and ether bond, which form with the polar groups on the surface of various polar base materials such as PET and PA. Hydrogen bonds, thereby forming joints with a certain connection strength.After the polyurethane resin is made into ink, it has excellent adhesion fastness when printed on the surface of polar plastic substrates.

3. Good affinity and wettability with pigments/dyes

Polyurethane resin for ink is generally prepared from polyester or polyether polyol, alicyclic diisocyanate and diamine/diol chain extender, with a molecular weight of approximately tens of thousands.Due to the introduction of urea bonds in PU resin, polyurethane-urea resin (PUU) is formed, which has good dispersion and wetting properties for pigments.

4.Good resin compatibility

Polyurethane resin for ink has good compatibility with aldehyde-ketone resin, chlorine-vinegar resin, etc. Users can add it appropriately according to the actual situation and their own process formula to improve the overall performance of the ink.

5．Excellent film forming properties

Ink polyurethane resin is structurally different from polyurethane resins used in other fields. Traditional polyurethane mainly reacts with polyester polyol/polyether polyol and isocyanic acid to form hydroxyl-terminated polyurethane resin. The polar group in the molecular structure is carbamic acid. Mainly ester, the molecular cohesion is not enough to meet the film-forming performance requirements of resin for ink.Therefore, polyurethane resin for ink introduces urea group on the basis of traditional polyurethane, which greatly improves the cohesive strength and film-forming properties of the resin itself.

6. Wide compatibility with organic solvents and good solvent release

The dissolving effect of organic solvents on resin is to attract solute molecules through the polarity of solvent molecules, which is commonly known as like miscibility; traditional polyurethane resin has a wide range of compatibility with organic solvents, such as ketones, esters, benzene, etc. Non-alcoholic organic solvents are excellent solvents.However, in the process of making ink, in order to adjust the flow performance and viscosity of the ink, the addition of alcoholic organic solvents is essential. For traditional polyurethane resins, the addition of alcoholic solvents greatly reduces the stability of the resin system, often causing turbidity, Incompatibility phenomena such as flocculent precipitation.However, the presence of urea groups in polyurethane resin for ink makes its compatibility with alcohol a reality. However, it is worth pointing out that alcohol solvents are still pseudo-solvents. In the microscopic state, alcohol solvents wrap the polyurethane resin molecules instead of Like a true solvent, the ink made from polyurethane resin has good fluidity due to the molecular polarity running through the molecule.

Applications of polyurethane ink resin

①Selection of solvent

During the ink manufacturing process, considering the volatilization gradient of the overall solvent system of the ink, to improve the solvent release of the printing ink and reduce the organic solvent residue of the printed product solvent, the solvents used are often several mixed solvents with different volatilities.The main organic solvents used in the ink manufacturing process include toluene, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, n-propyl acetate, isopropyl alcohol, etc. Customers can adjust the volatility of the ink according to seasonal changes. adjust.

②Selection of pigments

Due to the large differences in pigment grades on the market today, the dispersion and ink stability of the same pigment from different manufacturers of the same resin often vary greatly in polyurethane inks. Therefore, it is recommended that users base their actual needs on their own. Customers need to choose pigments carefully.

③Selection of additives

Wax powder: The wax powder used in the production of polyurethane ink is often low molecular weight polyethylene wax, with a relative molecular weight of generally 1000 to 6000. It has good solubility in the organic solvents in the ink and has affinity with the polyurethane resin itself. Better and has good chemical stability.It mainly serves to increase the friction resistance of the ink film surface, and at the same time, it can appropriately alleviate the anti-stick resistance of the ink itself.

Dispersant: A type of surfactant, mainly used to moisten the surface of the pigment, shorten the ink manufacturing time, facilitate the dispersion of the pigment, and sometimes appropriately reduce the oil absorption of the pigment.When manufacturing high-concentration ink, it can reduce the yield value of the ink and prevent the aggregation and precipitation of pigment particles in the ink.

Adhesion promoter: The polyurethane resin used for ink contains a large number of polar groups. Even if the surface of non-polar substrates such as BOPP and PE is treated with surface corona, the surface tension is generally between 38 and 42 dynes. To improve the adhesion of polyurethane ink, The adhesion fastness on the surface of this type of substrate often requires the appropriate addition of titanate coupling agents or chlorinated polypropylene adhesion accelerators.

Ink binder resin is an extremely critical raw material in the production of ink. It not only serves as a bridge between the color material and the base material, but also gives the ink various excellent physical properties.In ink production, choosing the right resin connecting material directly affects the performance of the ink on various substrates and the process adaptability during the printing process.When selecting resin, the physical properties of the resin must be fully considered to match the performance that the ink needs to achieve.

Polyurethane resin is a versatile material that can be used in the preparation of gravure printing ink for film. Gravure printing is a method of printing that uses engraved cylinders to transfer ink onto a substrate, and it is commonly used for high-volume printing applications such as packaging and labeling.

as a binder to provide adhesion and durability to the ink. It can also be used to adjust the viscosity and flow properties of the ink, which is important for ensuring consistent print quality and optimal ink transfer to the substrate.

We could provide solvent based polyurethane resin, polyurethane emulsion, acrylic resin, waterborne polyurethane dispersion to meet diversified requirement.

GRS (Global Recycled Standard) is a globally recognized certification and labeling system for products made from recycled materials. The purpose of GRS is to promote the use of recycled materials, reduce the environmental impact of production, and provide transparency and assurance to consumers. By using products certified under the Global Recycled Standard, consumers can make more informed choices, supporting sustainability and reducing waste by promoting the use of recycled materials.

To achieve GRS certification, companies must meet specific criteria related to the recycled content of their products. This includes ensuring that a minimum percentage of the product's materials come from recycled sources and maintaining traceability throughout the supply chain. GRS also takes into account issues such as environmental management, social responsibility, chemical use, and labeling.

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TPU (Thermoplastic Polyurethane) resin can be produced using both virgin and recycled materials. Recycled TPU resin is made from post-industrial or post-consumer waste, which is collected and processed to create new TPU resin. The use of recycled TPU resin helps to reduce waste and conserves resources. Koslen TPU is on the process to obtain GRS (Global Recycled Standard) certification. We can provide GRS (Global Recycled Standard) certification to the industries that standard covered soon, including textiles, apparel, home furnishings, and personal care products.

To maximize the space utilization and load as much E-TPU granule as possible in a 40" container, you can consider the following packing method:

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Use bulk bags (also known as FIBCs or super sacks): These large, flexible bags are commonly used for storing and transporting granular materials. Opt for high-capacity bulk bags that can hold a significant amount of E-TPU granule.

Optimize bag size: Choose the appropriate size of bulk bags that can efficiently fit inside the container. Larger bags with higher capacities will maximize the space utilization.

Stacking arrangement: Ensure efficient stacking of the bulk bags. Stack them in a way that optimizes the use of vertical space while maintaining stability. Place the bags in neat, compact rows and stack them as high as possible without compromising safety.

Eliminate empty spaces: Fill any empty spaces or gaps between the bags with smaller packages or dunnage materials, such as air pillows or foam blocks. This will prevent movement and shifting of the granules during transportation.

Secure the load: Make sure to secure the stack of bags properly using straps or other tie-down methods to prevent them from shifting or falling during transit.

Utilize container space: Load the stacked bags into the container in a way that evenly distributes the weight and optimizes the available space. Consider utilizing both the floor space and vertical space within the container.

Plus, please note store it properly: After packing, store the E-TPU granules in a cool, dry, and well-ventilated area. Avoid exposure to direct sunlight, extreme temperatures, or high humidity, as these can affect the quality of the granules.

With the development of China's economy and cultural undertakings, the printing and publishing industry and packaging industry have developed rapidly. Domestic demand for ink has increased dramatically. As people's environmental awareness increases and people's demand for safety in food packaging and printing increases, it is required that the proportion of aromatic hydrocarbons and toxic volatile organic components in the ink composition be reduced. Environmentally friendly inks have gradually experienced benzene-free inks, alcohol-soluble inks and water-based inks, and gradually replaced traditional volatile organic solvent-based inks. Polyurethane ink has gradually developed rapidly due to its unique performance advantages. It has the advantages of easy use, stable performance, strong adhesion, excellent gloss, and good heat resistance, and can be suitable for various printing methods. At the same time, polyurethane ink can be dissolved in solvents such as alcohol, ester, ketone or their mixed solvents without relying on highly toxic benzene solvents. It meets environmental protection requirements and has become the development direction and trend of the printing industry. Among the factors that determine the various properties of printing inks, the properties of the resin used in the ink are the main factors. Polyurethane resin has excellent wear resistance, scratch resistance, solvent resistance, bonding properties, good low-temperature performance, high gloss, and heat preservation, and its application properties are widely adjustable and can meet various needs. .

1 . Classification of polyurethane ink

Polyurethane ink can be divided into four main types according to the composition of the binder used and the curing principle: single-component volatile polyurethane ink, two-component reactive polyurethane ink, light-curing polyurethane ink and water-based polyurethane ink ; according to the printing format According to different printing substrates, it can be divided into plastic ink, paper ink, aluminum thin ink, printed fabric ink and ceramic ink, etc. For its special purposes, it can be divided into UV ink, luminescent, fluorescent and phosphorescent ink, liquid crystal, conductive and magnetic ink, retort-resistant ink and anti-counterfeiting ink, etc.

2 . Development status of polyurethane resin for ink

2. 1 Polyurethane resin for one-component volatile ink

Volatile polyurethane ink has the advantages of easy use and stable performance, and can meet the requirements of various printing methods. It is mainly used in plastic composite packaging and other aspects. It has been industrialized at home and abroad and has been widely used. The main synthesis mechanism of this type of ink is through the volatilization of a large amount of volatile solvents contained in it, so that the resin and pigment in the ink form a solid film layer that adheres to the surface of the substrate to achieve the purpose of printing. The advantages of this method are uniform reaction, easy control, and good reproducibility. One-component polyurethane resin for ink has good adhesion, oil resistance and cooking resistance on many plastic substrates .

GOLD MINE COMPANY as polyurethane resin manufacturer used adipic acid (AA) and 1,4- butanediol (BDO) as the basic raw materials to synthesize polyester polyols with a relative molecular weight of 1000 to 2000 and chain extenders, diphenylmethane diisocyanate (MDI). A one-component polyurethane ink connecting material is synthesized with other additives. The polyurethane ink has the characteristics of good gloss, low viscosity, and good bonding strength. It can meet the needs of the composite film and ink printing industries. It has been used in Guangdong and Fujian. Promote use in other areas. Zhou Wenxin et al. used a vinyl chloride - hydroxyethyl acrylate copolymer containing hydroxyl groups in the molecule to react with a macromolecular glycol, a small molecule chain extender, and toluene diisocyanate (TDI) to prepare a new type of polyurethane adhesive. The ink produced with it has good adhesion to various base films such as polypropylene (PP) and polyethylene (PE) . A polyurethane resin for inks developed by Japan's Sanyo Chemical Co., Ltd. is composed of polybutylene adipate glycol (PBA , with a maximum relative molecular mass of 1500) , isophorone diisocyanate (IPDI) , and isophorone Made from diamine (IPDA) and diethanolamine, due to the introduction of urea bonds and amine groups, the intermolecular hydrogen bonding force is greatly increased, improving the cohesive strength of the resin and the adhesion to the film. Made of 30 parts of resin and 50 parts of titanium dioxideThe plastic film printing ink prepared by adding 100% and several parts of mixed solvent has good printing effect on PP , polyethylene terephthalate (PET) and nylon films. The printing layer is resistant to heat grease and adhesion.

2. 2 Polyurethane resin for two-component reactive ink

Two-component ink is also called chemical reaction ink. A catalyst must be added before printing. The catalyst reacts with the resin in the ink to achieve the purpose of drying the ink through a polymerization reaction. Component A is a hydroxyl-terminated prepolymer and pigment. A mixture of other additives, component B is a curing agent with an isocyanate terminal group. When used, the two components are mixed in a certain proportion to print. This two-component reactive polyurethane ink has good adhesion and viscosity stability to plastic films. Component A has stable performance, low relative molecular weight, good fluidity, and good wettability to pigments; but in component B, due to the presence of isocyanate groups, this component has great Toxicity. In addition, the isocyanate group is a very reactive group and can easily react with water and other compounds containing active hydrogen at room temperature. Therefore, this component has poor stability and is difficult to store. Currently, two-component reactive polyurethane inks have many problems: the main components must be mixed with the curing agent quickly before printing, the ink cannot be touched by hands, the service life of canned products is very short, and the remaining ink after printing is easy to deteriorate. Moreover, the curing agent is expensive, which increases the cost of packaging bags or containers .

2.3 Polyurethane resin for photocurable ink

Polyurethane resin for light-curing inks uses high-intensity radiation such as electron beam radiation and ultraviolet radiation to induce cross-linking and curing of the active oligomer system. Considering factors such as equipment investment, ultraviolet (UV) curing is currently the main form. It has the advantages of cold curing, fast curing, energy saving, etc., and due to the use of a 100 % active component system, no solvent is released during the curing process, which greatly reduces pollution. The curing reaction mechanism of light-curing polyurethane ink is free radical polymerization. It can be cured in a few seconds and is suitable for high-speed printing. Since the reaction is a dry cross-linking process, it has good adhesion to most substrates. As a new type of environmentally friendly ink, UV curable ink has the advantages of energy saving, no solvent emission, no environmental pollution, high production efficiency, suitable for heat-sensitive substrates, excellent printing performance, and low equipment investment. It is widely used in paper and plastics , metal, paint film and other printing surfaces are extremely widely used. The entire curing system of UV curing is a solvent-free system, which is in line with green and environmentally friendly inks. UV ink printing has stable adaptability, can improve actual production efficiency and reduce costs, and can bring economic benefits such as high productivity and high output to investors .

2.4 Polyurethane resin for water-based ink

Water-based inks are listed as the first choice for environmentally friendly printing. The normal temperature cross-linked water-based polyurethane epoxy adhesive can produce a one-component polyurethane water-based ink suitable for gravure printing. The water-based ink has high gloss and water resistance, strong adhesion, adjustable dryness, bright colors, clear layers, non-toxic, non-flammable, weather-resistant, The viscosity is easy to control, and compared with other water-based inks, it has wide adaptability to various substrate materials. Polyurethane-polyacrylic acid. As a connecting material for water-based ink, during the drying process of ink film prints, the properties of polyurethane epoxy adhesive and polyacrylate are combined. The modified emulsion also has good adhesion fastness to the film. Compared with water-based acrylate, epoxy resin, etc., water-based polyurethane resin has more advantages in wear resistance, water resistance, chemical resistance, impact resistance, and balance of flexibility and hardness. Since it does not contain volatile organic solvents, it improves It improves the working environment, completely eliminates toxic and harmful substances in solvent-based inks, and eliminates contamination of packaged goods. It is mainly used for rotogravure printing machines to print food bags, shopping bags, fresh milk packaging bags, pharmaceutical packaging bags, sausage bags, candy bags, beverage bags, children's bags on EDM-treated PE , PP , PET, PVC and other films. Toy packaging bags and other packaging and printing products; at the same time, it is beneficial to protect the health of printing workers and consumers, reduce environmental pollution, etc., and represents the development direction of modern printing. Due to its own advantages and good compatibility with other resins, water-based polyurethane inks are constantly being improved and opening up more and more extensive application fields. At present, water-based polyurethane inks have been commercialized, can meet a variety of performance requirements, and are receiving more and more attention. The main applications of water-based polyurethane ink are flexographic printing and gravure printing. Water-based polyurethane ink, which is widely used abroad, is environmentally friendly and has good ink performance. It is mainly characterized by stable ink properties, high brightness, strong tinting power, and high adhesion fastness. , the drying speed can adapt to the needs of printing speed, and both four-color overprinting and spot color printing are available . E1-M011a MM[27] uses IPDI and polyethylene glycol (PEG, with relative molecular masses of 1000 and 2000) and hydroxyethyl methacrylate, using dibutyltin dilaurate as a catalyst, a water-based polyurethane was synthesized. The polyurethane has low viscosity, good fluidity, high dyeing strength and good environmental protection, and can be used in food packaging and medical supplies.

3 ．Prospects of polyurethane resin for ink

In recent years, the domestic plastic packaging industry has been changing rapidly, and the consumption of ink has increased significantly year by year. As people's living standards continue to improve, the demand for packaging inks is bound to further increase. Currently, our country accounts for 1/4 of the world's population, but our country's total ink production is less than 1/10 of the world's total production . The per capita consumption of ink is less than 1/24 of the world's top three average levels . The per capita consumption of printed matter is less than 1/24 of the world's average . It is still less than 1/20 of developed countries . Such a large gap shows that there is broad space for the development of my country's ink and the market development potential is huge. As people's environmental awareness gradually increases and people's demand for safety in food packaging and printing increases, the original benzene-containing ink connectors, although they have excellent performance, will eventually be eliminated because they are too toxic. Polyurethane ink connecting materials will develop rapidly in the future due to their unique performance advantages and environmental protection characteristics.

In addition, as China has become the fastest growing economy in the Asia-Pacific region, the world's major ink manufacturers have made major investment activities in China, such as Toyo Ink, SakataInx , DIC , Flint Ink, Donghua Ink, etc. In order to occupy the Chinese polyurethane ink market, many foreign companies have invested and built factories in China. Japan's Takeda Pharmaceutical Company's production plant in Suzhou has been put into production, providing ordinary low-priced polyurethane resins for inks to the Chinese market. The American Rohm and Haas Company has also set up a factory in Shanghai. After acquiring Morton Company, in addition to vigorously promoting water-based adhesives, it also sells polyurethane resins for solvent-based inks.