High-barrier coating for nylon film and preparation method of high-barrier coating

Abstract

The invention provides a high-barrier coating for a nylon film and a preparation method of the high-barrier coating. The high-barrier coating comprises a solvent and high-molecular-weight polyester polyol with a hydroxyl value of 3-10mgKOH / g, wherein the solvent is one or more of ethyl acetate, acetone, butanone, N, N-dimethylformamide, N-methyl pyrrolidone and N, N-dimethylacetamide, and the solvent is one or more of ethyl acetate, acetone, butanone, N, N-dimethylformamide, N-methyl pyrrolidone and N, N-dimethylacetamide; the macromolecular polyester polyol is prepared by carrying out polymerization reaction on polybasic acid, polyol and a fluorine-containing monomer in the presence of a catalyst; the fluorine-containing monomer is 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8-tridecafluoro-1-octanol, and the content of the fluorine-containing monomer is 0.01%-3% of the total mass. After a nylon film containing the coating is compounded with a polypropylene film by using an adhesive, the peeling strength of the nylon film and the polypropylene film after being cooked at the high temperature of 125 DEG C for 45 minutes is greater than 9N / 15mm, and the oxygen permeability of the finished film is less than 0.4 cm < 3 > / (m < 2 >. 24h. 0.1 Mpa). The high boiling strength at 125 DEG C for 45 minutes can meet the requirements of a high-temperature sterilization process of food, and the finished film has low oxygen permeability and can inhibit the color change of the food.

Description

Technical Field

[0001] The invention relates to the technical field of packaging materials, in particular to a high barrier coating for nylon film and a preparation method thereof. Background Art

[0002] Plastic packaging accounts for more than 30% of the total output value of the packaging industry, becoming a new force in the packaging industry, playing an irreplaceable role in food, beverages, daily necessities and industrial and agricultural production. In recent years, my country's plastic packaging industry has continued to develop rapidly, the scale of the industry continues to expand, and the development and application of new products, new materials and new equipment are changing with each passing day. It has formed a certain scale, occupied an important position in the packaging market, and played a positive role in the construction of the national economy.

[0003] Among plastic packaging materials, the market demand for film packaging accounts for about 40% of the total plastic packaging materials. Packaging films mainly include: heat shrink packaging film, winding packaging film, food aseptic packaging film, fruit and vegetable cling film, liquid packaging film, etc., which have been rapidly developed and widely used in recent years. With the rapid development of the packaging industry, more and more food packaging such as corn, chestnuts, fresh bamboo shoots, various canned fruits, and pre-prepared dishes have strong requirements for appearance, especially color and shelf life. Therefore, the research and development of high-barrier nylon film composite films that are resistant to high-temperature cooking have a strong demand for such packaging; however, the existing plastic film packaging materials cannot fully meet the use requirements in terms of strength and barrier properties. Products placed in the package for a long time are easily deteriorated and oxidized due to air penetration, which is often due to the poor performance of the packaging material, resulting in the inability to achieve long-term and effective preservation of the packaging.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In view of the fact that existing plastic film packaging materials cannot fully meet the use requirements in terms of strength and barrier properties, products placed in the packaging for a long time are easily deteriorated and oxidized due to air penetration. The present invention provides a high barrier coating for nylon film and a preparation method thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high barrier coating for nylon membrane, the high barrier coating comprising a solvent and a high molecular weight polyester polyol with a hydroxyl value of 3-10 mgKOH / g; wherein the solvent is one or more of ethyl acetate, acetone, butanone, N,N-dimethylformamide, N-methylpyrrolidone, and N,N-dimethylacetamide; the high molecular weight polyester polyol is prepared by polymerization reaction of a polyacid, a polyol, and a fluorine-containing monomer in the presence of a catalyst;

[0008] The polyacid is one or a combination of terephthalic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and 1,4-cyclohexanedicarboxylic acid;

[0009] The polyol is one or a combination of dodecanediol, tetradecanediol, and 1,4-cyclohexanedimethanol;

[0010] The fluorine-containing monomer is 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol, and the content of the fluorine-containing monomer is 0.01%-3% of the total mass.

[0011] Furthermore, the mass ratio of the polyacid to the polyol is 0.5-2.5:1, and the catalyst accounts for 0.0005%-0.004% of the total mass of the raw materials of the modified polyester polyol.

[0012] Furthermore, the catalyst is one or a combination of titanium catalysts and tin catalysts.

[0013] Furthermore, the polyacid or polyol contains at least one of 1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanedimethanol.

[0014] Further, the preparation method of the modified polyester polyol is: the polyacid, polyol and catalyst are stirred and dehydrated at 120-185°C for 1-6h, then the temperature is raised to 190-250°C, and vacuum is drawn until the vacuum degree is below -0.099Mpa, and then the temperature is set to 210-260°C for ester exchange reaction until the hydroxyl value is 3-10mgKOH / g, the reaction is terminated, and the pressure and temperature are reduced to discharge the material.

[0015] Furthermore, the high barrier coating also includes multifunctional isocyanate.

[0016] Furthermore, the mass ratio of the multifunctional isocyanate to the modified polyester polyol is 1:40-300.

[0017] The present invention also discloses a method for preparing a high barrier coating for nylon membrane as described above, comprising the following steps: dissolving a high molecular weight polyester polyol in a solvent at 50-90°C, adding the required multifunctional isocyanate, and reacting in a nitrogen atmosphere for 30-180 minutes, and then coating the reaction; coating is performed by direct coating or transfer coating on the nylon membrane, and after the solvent has evaporated, a barrier layer with a thickness of 1 micron is formed on the nylon membrane.

[0018] The invention also discloses a food packaging nylon film, wherein the food packaging nylon film comprises the high barrier coating.

[0019] The invention also discloses a packaging product, wherein the outer packaging structure of the packaging product comprises the above-mentioned food packaging nylon film.

[0020] Compared with the prior art, the present invention has the following beneficial effects: after the nylon film containing the coating is compounded with the polypropylene film with an adhesive, the peel strength of the nylon film and the polypropylene film after being steamed at 125°C for 45 minutes is greater than 9N / 15mm, and the oxygen permeability of the finished film is less than 0.4cm 3 / (m 2 ·24h·0.1Mpa). The high cooking intensity of 125℃45min can meet the requirements of high temperature sterilization process of food, and the low oxygen permeability of the finished film can inhibit the color change of food. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] This embodiment provides a high barrier coating for nylon membrane, which is prepared by the following method:

[0024] 1. Add 1.1kg of 1,4-cyclohexanedimethanol, 1kg of terephthalic acid, 0.01kg of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol and 0.005g of titanium catalyst to the reactor, start stirring, start heating to 160℃ and keep constant temperature for 3h, stabilize the dehydration rate (through the distillation tower, the top temperature is kept at 110℃), continue heating to 190℃ and turn on the vacuum pump, control the vacuum degree to gradually increase to -0.1MPa. Heat to 270℃ for transesterification reaction, and introduce nitrogen to take away excess polyols and small molecule alcohols. After 8h from the start of vacuuming, take samples every 2h for central control analysis until the final acid value is about (1.0-3.0)mgKOH / g and the hydroxyl value is 6.0mgKOH / g, restore normal pressure, reduce to 130℃, discharge and store, and obtain high molecular weight polyester polyol A.

[0025] 2. Add 0.6 kg of ethyl acetate, 0.38 kg of high molecular weight polyester polyol A, and 0.02 kg of hexamethylene diisocyanate isocyanurate trimer to the reactor in sequence, heat to 75 ° C in a nitrogen atmosphere and react for 90 minutes, then cool to 45 ° C, discharge and store to obtain coating liquid E.

[0026] Finally, the coating solution E is coated on the nylon membrane by direct coating or transfer coating, and a barrier layer with a thickness of 1 micron is formed on the nylon membrane after the solvent is evaporated.

[0027] Example 2

[0028] This embodiment provides a high barrier coating for nylon membrane, which is prepared by the following method:

[0029] 1. Add 0.8 kg of tetradecanediol, 1 kg of 1,4-cyclohexanedicarboxylic acid, 0.005 kg of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol and 0.007 g of tin catalyst to the reactor in sequence, turn on stirring, start heating to 160°C and keep the temperature constant for 3 hours, stabilize the dehydration rate (through the distillation tower, the top temperature is maintained at 110°C), continue to heat to 190°C, turn on the vacuum pump, and control the vacuum degree to slowly increase to -0.1 MPa. The temperature was raised to 275°C for transesterification reaction, and nitrogen was introduced to remove excess polyols and small molecule alcohols. After 8 hours from the start of vacuuming, samples were taken every 2 hours for central control analysis until the final acid value was about (1.0-3.0) mgKOH / g and the hydroxyl value was 3.0 mgKOH / g. Normal pressure was restored and reduced to 140°C. The material was discharged and stored to obtain high molecular weight polyester polyol B.

[0030] 2. Add 0.55 kg of butanone, 0.44 kg of high molecular weight polyester polyol B, and 0.01 kg of hexamethylene diisocyanate isocyanurate trimer to the reactor in sequence, heat to 85 ° C in a nitrogen atmosphere and react for 120 minutes, then cool to 45 ° C, discharge and store to obtain coating liquid F.

[0031] Finally, the coating liquid F is coated on the nylon membrane by direct coating or transfer coating, and after the solvent is evaporated, a barrier layer with a thickness of 1 micron is formed on the nylon membrane.

[0032] Example 3

[0033] This embodiment provides a high barrier coating for nylon membrane, which is prepared by the following method:

[0034] 1. Add 0.5 kg of tetradecanediol, 0.7 kg of 1,4-cyclohexanedimethanol, 1 kg of 1,4-cyclohexanedicarboxylic acid, 0.035 kg of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol and 0.007 g of titanium catalyst to the reactor in sequence, turn on stirring, start heating to 160 ° C and keep the temperature constant for 4 hours, stabilize the dehydration rate (through the distillation tower, the top temperature is maintained at 110 ° C), continue to heat to 190 ° C, turn on the vacuum pump, and control the vacuum degree to slowly increase to -0.1 MPa. The temperature was raised to 280°C for transesterification reaction, and nitrogen was introduced to remove excess polyols and small molecule alcohols. After 8 hours from the start of vacuuming, samples were taken every 2 hours for central control analysis until the final acid value was about (1.0-3.0) mgKOH / g and the hydroxyl value was 4.0 mgKOH / g. The pressure was restored to normal, the temperature was reduced to 120°C, and the material was discharged and stored to obtain high molecular weight polyester polyol C.

[0035] 2. Add 0.5 kg of N,N-dimethylformamide, 0.43 kg of high molecular weight polyester polyol C, and 0.01 kg of HB-100 (from Wanhua Chemical) was heated to 85°C in a nitrogen atmosphere for 150 minutes, then cooled to 70°C, discharged and stored to obtain coating liquid G.

[0036] Finally, the coating liquid G is coated on the nylon membrane by direct coating or transfer coating, and a barrier layer with a thickness of 1 micron is formed on the nylon membrane after the solvent is evaporated.

[0037] Example 4

[0038] This embodiment provides a high barrier coating for nylon membrane, which is prepared by the following method:

[0039] 1. Add 0.4 kg of dodecanediol, 1.1 kg of 1,4-cyclohexanedimethanol, 1.3 kg of 1,4-cyclohexanedicarboxylic acid, 0.045 kg of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol and 0.006 g of titanium catalyst to the reactor in sequence, turn on stirring, start heating to 160 ° C and keep the temperature constant for 4 hours, stabilize the dehydration rate (through the distillation tower, the top temperature is maintained at 110 ° C), continue to heat to 190 ° C, turn on the vacuum pump, and control the vacuum degree to slowly increase to -0.1 MPa. The temperature was raised to 275°C for transesterification reaction, and nitrogen was introduced to remove excess polyols and small molecule alcohols. After 8 hours from the start of vacuuming, samples were taken every 2 hours for central control analysis until the final acid value was about (1.0-3.0) mgKOH / g and the hydroxyl value was 5.5 mgKOH / g. The pressure was restored to normal and dropped to 140°C. The material was discharged and stored to obtain high molecular weight polyester polyol D.

[0040] 2. Add 0.4 kg of N,N-dimethylformamide, 0.57 kg of high molecular weight polyester polyol D, and 0.03 kg of HB-100 (from Wanhua Chemical) was heated to 85°C in a nitrogen atmosphere for 170 min, then cooled to 70°C, discharged and stored to obtain coating solution H.

[0041] Finally, the coating liquid H is coated on the nylon membrane by direct coating or transfer coating, and a barrier layer with a thickness of 1 micron is formed on the nylon membrane after the solvent is evaporated.

[0042] The EH coating liquid was coated on a nylon membrane (15 microns thick). After the solvent evaporated, the thickness of the dry adhesive layer on the nylon membrane was 1 micron. The solvent-based adhesive SBA4245N / XAS2283 (from HB Fuller, the coating amount of the solvent-based adhesive was 3.5 g / m 2 ) The nylon film containing dry glue is compounded with a polypropylene film (film thickness is 60 microns) to form a composite membrane EH containing an EH coating liquid.

[0043]

[0044] ① This peel strength is the peel strength of the composite film after being boiled at 125°C for 45 minutes, and the peeling speed is 300mm / min.

[0045] ②This test is in accordance with GB / T 1038-2000, test conditions: 23℃, 0%RH.

[0046] ③ Use composite film EH to package sweet corn or black corn, put it into 125℃ for 45 minutes for cooking test, and then leave it for 3 months to observe whether the color of the corn changes and whether the corn has any deterioration or odor.

[0047] The composite films G and H made of coating liquids G and H have good peel strength and low oxygen permeability, and are excellent in various properties for packaging sweet corn and black corn.

[0048] It should be noted that the above description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. In addition, the above are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

Claims

1. A high barrier coating for nylon membrane, characterized in that: The high barrier coating comprises a solvent and a high molecular weight polyester polyol having a hydroxyl value of 3-10 mgKOH / g; wherein the solvent is one or more of ethyl acetate, acetone, butanone, N,N-dimethylformamide, N-methylpyrrolidone, and N,N-dimethylacetamide; the high molecular weight polyester polyol is prepared by polymerization reaction of a polyacid, a polyol, and a fluorine-containing monomer in the presence of a catalyst; The polyacid is one or a combination of terephthalic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and 1,4-cyclohexanedicarboxylic acid; The polyol is one or a combination of dodecanediol, tetradecanediol, and 1,4-cyclohexanedimethanol; The fluorine-containing monomer is 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol, and the content of the fluorine-containing monomer is 0.01%-3% of the total mass.

2. A high barrier coating for nylon membrane as claimed in claim 1, characterized in that: The mass ratio of the polyacid to the polyol is 0.5-2.5:1, and the catalyst accounts for 0.0005%-0.004% of the total mass of the raw materials of the modified polyester polyol.

3. A high barrier coating for nylon membrane as claimed in claim 1, characterized in that: The catalyst is one or a combination of titanium catalysts and tin catalysts.

4. A high barrier coating for nylon membrane as claimed in claim 1, characterized in that: The polyacid or polyol contains at least one of 1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanedimethanol.

5. A high barrier coating for nylon membrane as claimed in claim 1, characterized in that: The preparation method of the modified polyester polyol is as follows: the polyacid, polyol and catalyst are stirred and dehydrated at 120-185°C for 1-6h, then the temperature is raised to 190-250°C, and vacuum is drawn until the vacuum degree is below -0.099Mpa, and then the temperature is set to 210-260°C for ester exchange reaction until the hydroxyl value is 3-10mgKOH / g, the reaction is terminated, and the pressure and temperature are reduced to discharge the material.

6. A high barrier coating for nylon membrane as claimed in claim 1, characterized in that: The high barrier coating further comprises a multifunctional isocyanate.

7. A high barrier coating for nylon membrane as claimed in claim 6, characterized in that: The mass ratio of the multifunctional isocyanate to the modified polyester polyol is 1:40-300.

8. A method for preparing a high barrier coating for a nylon membrane as claimed in claim 1, comprising the following steps: Dissolve the high molecular weight polyester polyol in a solvent at 50-90°C, add the required multifunctional isocyanate, and react in a nitrogen atmosphere for 30-180 minutes, and then wait for coating after the reaction is completed; The coating is performed by direct coating or transfer coating on the nylon film. After the solvent evaporates, a barrier layer with a thickness of 1 micron is formed on the nylon film.

9. A food packaging nylon film, comprising the high barrier coating according to any one of claims 1 to 7.

10. A packaged product, characterized in that: The outer packaging structure of the packaged product comprises the food packaging nylon film according to claim 9.

Images