Laminated adhesive and method for preparing laminated metal by using laminated adhesive

Abstract

The invention relates to an adhesive, in particular to a laminated adhesive and a method for manufacturing laminated metal by using the laminated adhesive. The invention provides a laminated adhesive, which is prepared from the following components in percentage by mass: 35 to 90 percent of fat epoxy resin, 5 to 61 percent of epoxy silicon resin, 0.5 to 1.0 percent of auxiliary agent and 3 to 10 percent of cationic curing agent, the invention also provides a preparation method of the laminated adhesive and a preparation method for preparing a laminated metal product by using the laminated adhesive. The laminated adhesive is environment-friendly, safe, simple to operate and high-temperature-resistant, can be applied to the field of metal packaging, and has a good market application prospect. The film-coated metal product prepared by the method has good adhesive force and boiling resistance, and can be applied to the field of food packaging.

Description

Technical Field

[0001] The invention relates to an adhesive, in particular to a film-coated adhesive and a method for preparing a film-coated metal by using the film-coated adhesive. Background Art

[0002] Laminating adhesive is an adhesive that bonds thin film materials to metal substrates. Laminating on the metal surface can increase the metal's corrosion resistance, increase the metal surface gloss, and beautify the metal surface, and is widely used in the field of metal packaging. Traditional metal laminating adhesives are mostly solvent-based. For example, Chinese patent CN112226201A discloses an oily laminating adhesive and its preparation method, which is composed of the following raw materials in parts by weight: 375-385 parts of toluene, 175-185 parts of xylene, 295-305 parts of thermoplastic rubber, 233-243 parts of petroleum resin, 327-337 parts of rosin, and 366-376 parts of organic solvent. The preparation method comprises: using a magnetic pump to pump the measured toluene, xylene and No. 120 solvent oil into a high-level tank respectively, putting the solvent in the high-level tank into a stirring tank, manually putting thermoplastic rubber into the stirring tank, and performing the first stirring, and then manually feeding rosin and petroleum resin into the stirring tank, and performing the second stirring, so that various raw materials are evenly dispersed to prepare an oily film-coating adhesive. The invention uses a large amount of solvent, and a large amount of volatile organic compounds (VOC) are generated during the preparation process, which is not friendly to the environment. Based on this, some improved technologies use water-based technology to solve the VOC problem. For example, Chinese patent CN101284978A discloses a water-based dry film-coating adhesive and a polymerization method. Based on the polymerization method of the water-based dry film-coating adhesive, the monomer is first pre-emulsified, and then the seed polymerization, continuous dripping reaction, elimination reaction, and finally the pH value and viscosity are adjusted. After passing the test, the material is filtered out with a filter. This technology overcomes the potential pollution problem of VOC and improves the environment, but most of the water-based technology is used in the field of printed flexible packaging and cannot be used in the field of metal packaging. The main reason is that it cannot meet the strict processing performance requirements and high temperature sterilization resistance requirements in the metal packaging field.

[0003] The above-mentioned traditional solvent-based and water-based laminating adhesive processes require that the metal sheet be treated with water and acid in the first step to remove oxides and residual oil on the metal surface, and then washed and dried to obtain a clean metal surface; the second step is to apply the glue to the surface of the metal sheet with a coating machine; the third step is to pre-dry the solvent or water at low temperature; the fourth step is to use a laminating machine to bond the coated metal sheet with the uncoated film material; the fifth step is to level the bonded metal sheet and film material; the sixth step is to heat and cure the leveled metal sheet and film material or to perform humidification curing for 48 hours, and then complete the lamination. The operation steps are cumbersome, or there is a defect of generating a large amount of volatile organic compounds (VOC) during the preparation process, or the application field is limited and cannot be applied to the field of metal packaging materials. It is urgent to develop an environmentally friendly, safe, and easy-to-operate laminating adhesive that can be applied to the field of metal packaging and a method for manufacturing laminated metal using the laminating adhesive. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention provides a coating adhesive and a method for manufacturing coated metal using the coating adhesive.

[0005] In one aspect, the present invention provides a coating adhesive. The coating adhesive is composed of the following components by weight percentage:

[0006]

[0007] Furthermore, the fatty epoxy resin in the coating adhesive is one of 3,4-epoxycyclohexylcarboxylic acid-3′,4′-epoxycyclohexyl methyl ester or bis(7-oxabicyclo[4.1.0]3-heptylmethyl)adipate, or diglycidyl tetrahydrophthalate or N,N-diglycidyl-4-glycidyloxyaniline.

[0008] Furthermore, the epoxy silicone resin in the coating adhesive is one of a tetrafunctional epoxy silicone modified resin or a dioxy-functional aliphatic epoxy silicone polymer or a diepoxy silicone resin or a polyepoxy silicone polymer or an epoxy tetrafunctional oligomer silicone resin.

[0009] Furthermore, the auxiliary agent in the coating adhesive includes polyether-modified polydimethylsiloxane or fluorocarbon-modified polyacrylate.

[0010] Furthermore, the cationic curing agent in the coating adhesive is a hexafluoroantimonic acid blocked amine salt or a trifluorosulfonic acid blocked amine salt.

[0011] On the other hand, the present invention provides a method for preparing a coating adhesive, which comprises weighing all components according to the component contents of the coating adhesive, adding the components into a dispersion blending tank, mechanically stirring for 30 minutes, and then filtering to obtain the coating adhesive.

[0012] In addition, the present invention also provides a method for preparing a coated metal using the coated adhesive, and the method for preparing the coated metal comprises the following steps:

[0013] Step 1: Coating

[0014] The coating adhesive is applied on the metal sheet or PET film with a coating thickness of 3 to 15 microns and a coating temperature of 25-35°C.

[0015] Step 2: Fit

[0016] The coated metal sheet and the PET film are completely bonded together by roller pressing, the transmission speed is 70m / min, the temperature of the pressing roller and the bonding roller is room temperature, and the pressure between the pressing roller and the bonding roller is greater than 0.5MPa.

[0017] Step 3: Curing

[0018] The product obtained in step 2 is placed at 120° C. and cured for 15 minutes to obtain a coated metal.

[0019] In addition, the film-coated adhesive of the present invention can be used to prepare film-coated metals; and the film-coated metals prepared by the method of the present invention can be used in the packaging field.

[0020] Compared with the prior art, the present invention has at least the following advantages or beneficial effects:

[0021] The present invention provides a laminating adhesive and a method for preparing the laminating adhesive, which overcomes the problem in the prior art that a large amount of volatile organic compounds are generated during the use of the laminating adhesive and can be applied to the field of metal packaging with strict preparation conditions.

[0022] Compared with the prior art, the method for preparing coated metal with the coating adhesive provided by the present invention is simple to operate, non-toxic and safe, only requires coating at room temperature, does not require cleaning of the plate, has no volatile organic compound emissions, is environmentally friendly and energy-saving, has mild curing conditions and a short curing time, and the prepared coated metal has better adhesion and boiling water resistance than the coated metal prepared by the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the coated iron structure. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described below in conjunction with embodiments; however, the present invention is not limited to the following embodiments.

[0025] The experimental methods and detection methods in the following embodiments are all conventional methods unless otherwise specified; the raw materials and materials are all commercially available unless otherwise specified; the index data are all conventional measurement methods unless otherwise specified.

[0026] Example 1

[0027] This embodiment provides the components of coated iron and the mass percentages of the components.

[0028] In this embodiment, the aliphatic epoxy resin S-06E (3,4-epoxycyclohexylcarboxylic acid-2′,4′-epoxycyclohexylmethyl ester), S-28 (bis(7-oxabicyclo[4.1.0]3-heptylmethyl) adipate), and S-182 (bisglycidyltetrahydrophthalate) were purchased from Yantai Donghua New Materials Co., Ltd.; S-510 (N,N-diglycidyl-4-glycidyloxyaniline) was purchased from Nantong Synasia New Materials Co., Ltd.

[0029] In this embodiment, epoxy silicone resin UN-DA4 (tetrafunctional epoxy silicone modified resin) and UM-052 (dioxyfunctional aliphatic epoxy silicone polymer) were purchased from Wuhan Enric Materials Co., Ltd.; PC-1000 (diepoxy silicone resin), PC-2004 (molecular weight 1000g / mol, polyepoxy silicone polymer), PC1035 (diepoxy silicone resin) were purchased from Polyset Corporation of the United States; KR-470 (epoxy tetrafunctional oligomer silicone resin) was purchased from Shin-Etsu Chemical Industry Co., Ltd.; MP-200 (epoxy functional oligomer) was purchased from Maitu High-Tech Materials Group.

[0030] In this example, the additives BYK-300 (polyether modified polydimethylsiloxane solution), BYK-301 (polyether modified polydimethylsiloxane copolymer solution), and BYK-306 (polyether modified polydimethylsiloxane solution) were purchased from BYK Additives (Shanghai) Co., Ltd.; Afcona3750 (fluorocarbon modified polyacrylate polymer) was purchased from Afcona Polymer Co., Ltd.

[0031] In this example, the curing agent DH081 (hexafluoroantimonic acid blocked ammonium salt) and DH091 (trifluorosulfonic acid blocked ammonium salt) were purchased from Yantai Donghua New Materials Co., Ltd.

[0032] The coating agent components of this embodiment and the mass percentage of each component are shown in Table 1.

[0033] Table 1 Coating agent components and mass percentage ratios of each component in Example 1

[0034]

[0035] Example 2

[0036] In this example, 7 groups of different coating agents were prepared.

[0037] According to the components and mass percentage of each component in Example 1, the aliphatic epoxy resin, epoxy silicone resin, auxiliary agent and curing agent were weighed respectively, and the total mass of each group was 100g. The aliphatic epoxy resin, epoxy silicone resin, auxiliary agent and curing agent weighed above were added to the dispersion blending tank respectively, and stirred by mechanical stirring at a stirring speed of 100r / min and a stirring time of 30min. After the stirring was completed, the stirred product was filtered to obtain 7 groups of coating adhesives.

[0038] Example 3

[0039] This example uses the coating adhesive prepared in Example 2 to prepare coated iron.

[0040] The coated iron product was prepared using the coating adhesive prepared in Example 2 according to the following steps.

[0041] Step 1: Coating

[0042] The coating adhesives of groups 1 to 3 prepared in Example 2 are applied on tinplate or PET film by knife coating, and the coating adhesives of groups 4 to 7 prepared in Example 2 are applied on tinplate or PET film by roller coating. The coating thickness is 3 to 15 microns, and the coating temperature is 25 to 35°C.

[0043] Step 2: Fit

[0044] The iron sheet coated in step 1 is completely bonded to the PET film by roller pressing, wherein the transmission speed is 70 m / min, the temperature of the pressing roller and the bonding roller is room temperature, and the pressure between the pressing roller and the bonding roller is greater than 0.5 MPa.

[0045] Step 3: Curing

[0046] The laminated iron products bonded in step 2 were placed at 120° C. for curing for 15 minutes. After the curing was completed, 7 groups of laminated iron products were obtained.

[0047] Implementation 4

[0048] This example is a performance test of coated iron products.

[0049] The performance test of coated iron products was divided into 1 control group and 7 experimental groups.

[0050] Comparative group: The single-component PUR adhesive model PUR-XZJ605 produced by Wuxi Wanli Adhesive Materials Co., Ltd. was used to prepare the peritoneal iron sample as follows: the first step was heating, PUR-XZJ605 was heated to 80°C in a closed tank, the second step was coating, the PUR-XZJ605 glue was coated on the tinplate or PET film by blade coating, and the coating thickness was about 3 to 15 microns; the third step was bonding, the iron sheet coated in the step 2 was completely bonded to the PET film by roller pressing, wherein the transmission speed was 70m / min, the temperature of the pressure roller and the bonding roller was room temperature, and the pressure between the pressure roller and the bonding roller was greater than 0.5MPa; the fourth step was curing, the bonded coated iron product was placed in a high temperature and wet heat box at 60°C and 80% humidity for 24 hours, and the comparative group test sample was obtained after curing.

[0051] Test group: 7 groups of coated iron prepared in Example 3.

[0052] The comparison group and the test group of coated iron were subjected to boiling water resistance test, adhesion test and impact resistance test respectively, and then the test results were analyzed to determine the performance of each group of coated iron. The test details are as follows:

[0053] Boiling resistance test: The control group of coated iron products and the seven test groups of coated iron products were tested in a pressure cooker at 121°C. The samples were boiled for 60 minutes to observe whether they turned white or had bubbles. If there was no corrosion, they were qualified. The boiling resistance test can simulate the high-temperature boiling state. Products that pass the test can be used in metal packaging that requires high-temperature sterilization or heating.

[0054] Adhesion test: The control group of coated iron products and the 7 groups of test group coated iron products were tested according to the method in the test standard GB / T9286-2021 "Scratch test for paints and varnishes".

[0055] Impact resistance test: The control group of coated iron products and the 7 groups of test group coated iron products were tested in accordance with the method in the test standard GB / T1732-2020 "Determination of impact resistance of paint film", according to the 50Kg impact level, and then immersed in 20% copper sulfate. The products were qualified if there were no corrosion spots.

[0056] The test results of the performance of the coated iron products are shown in Table 2. The results show that the coated iron prepared by the coating agent of the present invention according to the method provided by the present invention has a level 1 adhesion, no whitening in boiling water resistance, and no bubbles after boiling the film. The 50Kg impact test shows that the impact resistance of the coated iron groups 4 and 5 is all level 1, and has good mechanical processing performance. Comprehensive comparison shows that the coated iron prepared by the present invention is better than the control group in adhesion performance, better than the control group in boiling water resistance, and can meet the impact resistance performance of metal material packaging in impact resistance performance. The comprehensive comparison performance is better than the control group. The coated iron prepared by the coating agent and preparation method provided by the present invention can be used in the field of food packaging.

[0057] Table 2 Test results of coated iron performance

[0058]

[0059] As described above, the present invention can be well implemented. The above embodiments only describe the preferred implementation methods of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various changes and improvements made to the technical scheme of the present invention by ordinary technicians in this field should fall within the protection scope determined by the present invention.

Claims

1. A coating adhesive, characterized in that: The coating adhesive is composed of the following components by weight percentage:

2. The film-coating adhesive according to claim 1, characterized in that: The aliphatic epoxy resin is one of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester or bis(7-oxabicyclo[4.1.0]3-heptylmethyl)adipate, or tetrahydrophthalic acid bisglycidyl ester or N,N-diglycidyl-4-glycidyloxyaniline.

3. The film-coating adhesive according to claim 1, characterized in that: The epoxy silicone resin is one of tetrafunctional epoxy silicone modified resin, dioxyfunctional aliphatic epoxy silicone polymer, diepoxy silicone resin, polyepoxy silicone polymer, or epoxy tetrafunctional oligomer silicone resin.

4. The laminating adhesive according to claim 1, characterized in that: The auxiliary agent comprises polyether-modified polydimethylsiloxane or fluorocarbon-modified polyacrylate.

5. The laminating adhesive according to claim 1, characterized in that: The cationic curing agent is hexafluoroantimonic acid blocked amine salt or trifluorosulfonic acid blocked amine salt.

6. A method for preparing the film-coating adhesive according to claim 1, characterized in that: The components described in claim 1 are weighed in proportion, added into a dispersion blending tank, stirred and filtered to obtain the coating adhesive.

7. The method for preparing the coating adhesive according to claim 6, characterized in that: The stirring method is mechanical stirring, and the stirring time is 30 minutes.

8. A method for preparing coated metal using the coating adhesive according to claim 1, characterized in that: The method comprises the following steps: Step 1: Coating The coating adhesive is applied on the metal sheet or PET film with a coating thickness of 3 to 15 microns and a coating temperature of 25-35°C. Step 2: Fit The coated metal sheet and the PET film are completely bonded together by roller pressing, the transmission speed is 70m / min, the temperature of the pressing roller and the bonding roller is room temperature, and the pressure between the pressing roller and the bonding roller is greater than 0.5MPa. Step 3: Curing The product obtained in step 2 is placed at 120° C. and cured for 15 minutes to obtain a coated metal.

9. The coating adhesive according to claim 1 is used for preparing coated metal.

10. The film-coated metal prepared by the method according to claim 8 is applied in the field of food packaging.

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