With the improvement of the market's requirements for the safety performance of raw materials for flexible packaging, as far as technology is concerned, the adhesive used will develop towards water-based and solvent-free. Under current technical conditions, water-based adhesives have poor adaptability in the use of plastics, aluminum foils and other materials, and the investment cost of solvent-free adhesives equipment is too large to be promoted in the near future. Alcohol-soluble polyurethane adhesives have characteristics of cost-effectiveness, safety, and hygiene. Has been accepted by more and more customers. Here are some of the application advantages of the alcohol-soluble polyurethane adhesive in the compounding process.
1. The alcohol-soluble polyurethane adhesive can avoid the phenomenon of weak bonding due to moisture. The insufficiency of adhesion in the composite film is mainly due to insufficient curing dose, less amount of glue, improper corona treatment on the film surface, high water content in the solvent, Problems with the ink connecting material and the migration of chemicals. Among them, insufficient curing doses and weak adhesion due to solvent moisture content occur frequently, especially in the rainy season in the south, hot weather and the humid climate in the southwest region. Excessive moisture in the environment will replace the main agent. The hydroxyl group reacts with the hardener of the ester-soluble adhesive, resulting in a misalignment of the main agent and the hardener, causing the composite film to be loosely bonded and often accompanied by air bubbles. The main agent and hardener of the alcohol-soluble polyurethane adhesive do not react chemically with water, so that the phenomenon of inadequacy of adhesion due to unavoidability can be avoided.
Alcohol-soluble polyurethane adhesive can avoid the fear of water content in the solvent Ester-soluble adhesives generally use ethyl acetate as the solvent. Due to the differences in the procurement channels and the climate, ethyl acetate often has excessive water content. The situation, in turn, affects the product quality of the composite film. Alcohol-soluble adhesives use inexpensive industrial alcohol as a solvent, allowing a certain amount of moisture to be present, thus eliminating the need for purchase and use. Especially for some users with poor detection ability, the measurement of water content can be reduced, saving energy and material resources.
3. Alcohol-soluble adhesive can eliminate the white point of the aluminized film and the packaging machine 'target = _blank> transparent film's small crystal point aluminized film composite easily produces white spots, especially in white ink and yellow ink. The reasons are different. In most cases, it is due to insufficient glue and defects in the adhesive itself. In order to eliminate white spots, the amount of sizing for general ester-soluble adhesives needs to be 2.6g/m2 (dry basis), and alcohol-soluble adhesives have a molecular weight of 2.0g/m2 (dry basis) due to their own molecular structure. It can eliminate composite white spots.
Small crystals occur on the packaging machine 'target=_blank> transparent film, there are more convex and concave. The protruding small crystal spots are mostly caused by the glue, the network roller and the air humidity. The main component is the cured adhesive particles. With alcohol-soluble adhesives, bumps can be avoided as long as the environment is clean. The concave small crystal point is mainly caused by excessive water. A careful observation with a magnifying glass reveals that there are small bubbles. The alcohol-soluble adhesive itself has a good leveling property and is not sensitive to water, so it can basically eliminate the small recesses. Crystal point.
4. Alcohol-soluble adhesives can effectively solve the problem of high solvent residues. Alcohol-soluble adhesives use ethanol as the solvent. There are no -NCO groups and highly toxic aromatic isocyanate molecules such as free TDI and MDI in the monomer; as a "green solvent", The toxicity of ethanol is much lower than that of ethyl acetate. Therefore, the use of alcohol-soluble adhesives for compounding does not produce residual toluene, ethyl ester, TDI, MDI, etc., and only a trace amount of alcohol remains, which can greatly reduce the residual amount of solvent. .
5. Alcohol-soluble adhesives can solve the problem of matching with alcohol-soluble inks. With the popularity of non-benzene-based packaging in China, alcohol-soluble inks are being used by more and more manufacturers, because alcohol-soluble polyurethane printing inks inevitably have Residual alcoholic solvents are present, while the alcoholic solvents can be combined with ester-soluble adhesives to reduce the build-up fastness. Severe conditions can cause delamination. Therefore, in this case, excellent composite strength can be obtained by using an alcohol-soluble adhesive and an alcohol-soluble ink.
6. Alcohol-soluble adhesives can avoid the problem of composite through-holes (tunnels). Commonly referred to as "through-hole" phenomenon, it generally refers to the appearance of transverse stripes in composite products, especially at both ends of the material. This wrinkle is flat with a composite substrate, and another kind of bulge forms a through hole (also called a tunnel). The cause of this phenomenon is mainly caused by the tension of the substrate, the winding tension after compounding, and the initial tack of the adhesive. If the initial adhesion is very small and the adhesive force is insufficient, when a substrate shrinks, relative displacement occurs between the upper and lower two different substrates, ie wrinkles and through-holes. Therefore, it is the first choice to solve this problem by choosing a large adhesive force. Since alcohol-soluble adhesives have a much higher initial viscosity than ester-soluble adhesives, composite vias (tunnels) can be avoided during composite production.
7. Alcohol-soluble adhesives can meet the safety requirements of foods, pharmaceuticals, and export packaging. With China's accession to the WTO, developed countries set more and more technical barriers to China's exports. In addition, the development of the domestic economy has become more and more. The food company's pharmaceutical company raised the issue of safety and hygiene of packaging materials, and in particular, there are more and more restrictions on the release of the strong carcinogen TDA (toluene diamine) due to hydrolysis. The alcohol-soluble adhesives do not contain -NCO groups, TDI, and other substances because the main agent and the curing agent do not produce TDA. Therefore, they are non-toxic and hygienic in the production and application of the composite film, and are in compliance with foods, medicines, and pharmaceuticals. Safety requirements for export packaging.
8. Alcohol-soluble adhesive requires a short maturation time The alcohol-soluble adhesive requires a low maturation temperature, a short maturation time, and even aging at room temperature. Save energy for color printing plants and shorten the delivery time of products.
9. Alcohol-soluble adhesives have a superior cost performance due to the molecular structure relationship, with the same anilox roller sizing, the same concentration of the working solution, alcohol-soluble adhesive glue than the ester-soluble adhesive 20-25% lower. Coupled with the corresponding difference in solvent prices, the actual cost of alcohol-soluble adhesives is not high. In particular, with the large-scale production of the US-funded enterprise-European-American Industrial (Shenzhen) Co., Ltd., the actual use cost has been lower than some common ester-soluble adhesives.
With the increasing understanding of alcohol-soluble adhesives, more and more applications of alcohol-soluble adhesives have been made in China. These color printing plants using alcohol-soluble adhesives not only contributed to the protection of the environment, but also enhanced the company's image and were recognized by some multinational food companies.
1. The alcohol-soluble polyurethane adhesive can avoid the phenomenon of weak bonding due to moisture. The insufficiency of adhesion in the composite film is mainly due to insufficient curing dose, less amount of glue, improper corona treatment on the film surface, high water content in the solvent, Problems with the ink connecting material and the migration of chemicals. Among them, insufficient curing doses and weak adhesion due to solvent moisture content occur frequently, especially in the rainy season in the south, hot weather and the humid climate in the southwest region. Excessive moisture in the environment will replace the main agent. The hydroxyl group reacts with the hardener of the ester-soluble adhesive, resulting in a misalignment of the main agent and the hardener, causing the composite film to be loosely bonded and often accompanied by air bubbles. The main agent and hardener of the alcohol-soluble polyurethane adhesive do not react chemically with water, so that the phenomenon of inadequacy of adhesion due to unavoidability can be avoided.
Alcohol-soluble polyurethane adhesive can avoid the fear of water content in the solvent Ester-soluble adhesives generally use ethyl acetate as the solvent. Due to the differences in the procurement channels and the climate, ethyl acetate often has excessive water content. The situation, in turn, affects the product quality of the composite film. Alcohol-soluble adhesives use inexpensive industrial alcohol as a solvent, allowing a certain amount of moisture to be present, thus eliminating the need for purchase and use. Especially for some users with poor detection ability, the measurement of water content can be reduced, saving energy and material resources.
3. Alcohol-soluble adhesive can eliminate the white point of the aluminized film and the packaging machine 'target = _blank> transparent film's small crystal point aluminized film composite easily produces white spots, especially in white ink and yellow ink. The reasons are different. In most cases, it is due to insufficient glue and defects in the adhesive itself. In order to eliminate white spots, the amount of sizing for general ester-soluble adhesives needs to be 2.6g/m2 (dry basis), and alcohol-soluble adhesives have a molecular weight of 2.0g/m2 (dry basis) due to their own molecular structure. It can eliminate composite white spots.
Small crystals occur on the packaging machine 'target=_blank> transparent film, there are more convex and concave. The protruding small crystal spots are mostly caused by the glue, the network roller and the air humidity. The main component is the cured adhesive particles. With alcohol-soluble adhesives, bumps can be avoided as long as the environment is clean. The concave small crystal point is mainly caused by excessive water. A careful observation with a magnifying glass reveals that there are small bubbles. The alcohol-soluble adhesive itself has a good leveling property and is not sensitive to water, so it can basically eliminate the small recesses. Crystal point.
4. Alcohol-soluble adhesives can effectively solve the problem of high solvent residues. Alcohol-soluble adhesives use ethanol as the solvent. There are no -NCO groups and highly toxic aromatic isocyanate molecules such as free TDI and MDI in the monomer; as a "green solvent", The toxicity of ethanol is much lower than that of ethyl acetate. Therefore, the use of alcohol-soluble adhesives for compounding does not produce residual toluene, ethyl ester, TDI, MDI, etc., and only a trace amount of alcohol remains, which can greatly reduce the residual amount of solvent. .
5. Alcohol-soluble adhesives can solve the problem of matching with alcohol-soluble inks. With the popularity of non-benzene-based packaging in China, alcohol-soluble inks are being used by more and more manufacturers, because alcohol-soluble polyurethane printing inks inevitably have Residual alcoholic solvents are present, while the alcoholic solvents can be combined with ester-soluble adhesives to reduce the build-up fastness. Severe conditions can cause delamination. Therefore, in this case, excellent composite strength can be obtained by using an alcohol-soluble adhesive and an alcohol-soluble ink.
6. Alcohol-soluble adhesives can avoid the problem of composite through-holes (tunnels). Commonly referred to as "through-hole" phenomenon, it generally refers to the appearance of transverse stripes in composite products, especially at both ends of the material. This wrinkle is flat with a composite substrate, and another kind of bulge forms a through hole (also called a tunnel). The cause of this phenomenon is mainly caused by the tension of the substrate, the winding tension after compounding, and the initial tack of the adhesive. If the initial adhesion is very small and the adhesive force is insufficient, when a substrate shrinks, relative displacement occurs between the upper and lower two different substrates, ie wrinkles and through-holes. Therefore, it is the first choice to solve this problem by choosing a large adhesive force. Since alcohol-soluble adhesives have a much higher initial viscosity than ester-soluble adhesives, composite vias (tunnels) can be avoided during composite production.
7. Alcohol-soluble adhesives can meet the safety requirements of foods, pharmaceuticals, and export packaging. With China's accession to the WTO, developed countries set more and more technical barriers to China's exports. In addition, the development of the domestic economy has become more and more. The food company's pharmaceutical company raised the issue of safety and hygiene of packaging materials, and in particular, there are more and more restrictions on the release of the strong carcinogen TDA (toluene diamine) due to hydrolysis. The alcohol-soluble adhesives do not contain -NCO groups, TDI, and other substances because the main agent and the curing agent do not produce TDA. Therefore, they are non-toxic and hygienic in the production and application of the composite film, and are in compliance with foods, medicines, and pharmaceuticals. Safety requirements for export packaging.
8. Alcohol-soluble adhesive requires a short maturation time The alcohol-soluble adhesive requires a low maturation temperature, a short maturation time, and even aging at room temperature. Save energy for color printing plants and shorten the delivery time of products.
9. Alcohol-soluble adhesives have a superior cost performance due to the molecular structure relationship, with the same anilox roller sizing, the same concentration of the working solution, alcohol-soluble adhesive glue than the ester-soluble adhesive 20-25% lower. Coupled with the corresponding difference in solvent prices, the actual cost of alcohol-soluble adhesives is not high. In particular, with the large-scale production of the US-funded enterprise-European-American Industrial (Shenzhen) Co., Ltd., the actual use cost has been lower than some common ester-soluble adhesives.
With the increasing understanding of alcohol-soluble adhesives, more and more applications of alcohol-soluble adhesives have been made in China. These color printing plants using alcohol-soluble adhesives not only contributed to the protection of the environment, but also enhanced the company's image and were recognized by some multinational food companies.
Packing Tape,Hot Melt Tape Printing Adhesive Tape Co., Ltd. , http://www.nspackingtape.com