Environmentally friendly water-based release agent, and water-based release film and application method therefor

Abstract

The present application relates to the field of film materials, and specifically discloses an environmentally friendly water-based release agent, and a water-based release film and an application method therefor. The environmentally friendly water-based release agent comprises a modified acrylic resin and a coating composition used in combination. The raw materials for the modified acrylic resin comprise: a self-crosslinking acrylic resin, an acrylate copolymer and an antioxidant. The raw materials for the coating composition comprise a hydroxyl acrylic copolymer dispersion, a water-based slipping and anti-wear agent, a curing agent, a water-based drier and deionized water. A modified acrylic resin is used as a primer coat for the water-based release film; and by modifying an acrylic resin and using same in combination with a hydroxyl acrylic copolymer dispersion, the surface strength and stability of the release film can be improved. The water based release film can meet the standards of available silicone release films in terms of parameters such as peel force, adhesion strength and stability; moreover, the water based release film generates only a very small amount of VOC waste gas, is environmentally friendly and has low costs.

Description

An environmentally friendly waterborne release agent, a waterborne release film, and a method for implementing the same. Technical Field

[0001] This application relates to the field of thin film materials, and more specifically, to an environmentally friendly waterborne release agent, a waterborne release film, and a method for implementing the same. Background Technology

[0002] Release films, as an important functional film material, are widely used in electronics, packaging, printing, medical, and other fields. Their main function is to provide an easily peelable surface without damaging the substrate, thus protecting the surface quality of products during processing, transportation, and storage. Traditional release films primarily use silicone release agents and fluorinated release agents.

[0003] Silicone release agents dominate the release film field due to their excellent release properties and chemical stability. However, their production process generates volatile organic compounds (VOCs), which not only pollute the environment but also increase environmental protection costs for companies. To comply with increasingly stringent environmental regulations, companies need to invest heavily in the construction and operation of waste gas treatment facilities, which undoubtedly increases production costs and places higher demands on production equipment and the workshop environment.

[0004] While fluorinated release agents outperform silicone release agents in certain aspects, such as lower surface energy and better chemical resistance, their high price limits their application in a wider range of fields. Fluorinated release agents are mainly used in high-end markets with extremely high performance requirements, such as the manufacture of high-end electronic products. However, their high cost and potential environmental problems (such as fluoride emissions) have also become factors restricting their development.

[0005] In view of the above problems, the development of a new type of release film that is environmentally friendly, cost-effective and has excellent performance has become an urgent need in the industry. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides an environmentally friendly waterborne release agent, a waterborne release film, and a method for implementing the same.

[0007] The technical solution adopted in this application is as follows:

[0008] In a first aspect, this application provides an environmentally friendly waterborne release agent comprising a modified acrylic resin and a coating composition used in combination;

[0009] The raw materials for the modified acrylic resin include: self-crosslinking acrylic resin, acrylate copolymer, and antioxidant;

[0010] The raw materials of the coating composition include hydroxy acrylic copolymer dispersion, water-based slip and wear-resistant agent, curing agent, water-based drying agent and deionized water;

[0011] The mass ratio of the modified acrylic resin to the coating composition is (75-104):(40-60).

[0012] Furthermore, the raw materials for the above-mentioned modified acrylic resin include, by weight parts:

[0013] 30-50 parts of self-crosslinking acrylic resin, 1-4 parts of acrylate copolymer, and 1-3 parts of antioxidant.

[0014] Preferably, the mixture comprises, by weight, 35-45 parts of self-crosslinking acrylic resin, 2-3 parts of acrylate copolymer, and 2-3 parts of antioxidant.

[0015] Furthermore, the modified acrylic resin described above is obtained through the following method:

[0016] According to the weight parts, the self-crosslinking acrylic resin and the acrylate copolymer are mixed and stirred evenly, and then the antioxidant is added and mixed.

[0017] The modified acrylic resin obtained by the above method, due to its self-crosslinking property of spontaneously forming a crosslinked network structure, can impart higher cohesive strength and solvent resistance to the release film, thereby improving its stability and surface adhesion. Simultaneously, the introduction of the acrylate copolymer helps to regulate the surface energy of the release film, ensuring good release performance while effectively preventing adhesion between the adhesive and the substrate.

[0018] Further, the above coating composition comprises, by weight parts:

[0019] 70-90 parts of hydroxyl acrylic acid copolymer dispersion; 1-3 parts of water-based lubricating and wear-resistant agent; 1-3 parts of curing agent; 1-5 parts of water-based drying agent; 1-3 parts of water.

[0020] Preferably, the hydroxyl acrylic acid copolymer dispersion comprises 75-85 parts; water-based lubricating and wear-resistant agent comprises 1.5-2.5 parts; curing agent comprises 1.5-2.5 parts; water-based drying agent comprises 1.5-2.5 parts; and water comprises 1.5-2.5 parts.

[0021] Furthermore, the aforementioned water-based lubricating and wear-resistant agents include any one of polydimethylsiloxane, polyphenylmethylsiloxane, and polyether-modified polydimethylsiloxane.

[0022] By selecting a suitable water-based lubricating and wear-resistant agent, the wear resistance and anti-sticking effect of the release film surface can be increased. Combined with a hydroxyl acrylic copolymer dispersion, this results in a release film with lower release force. Preferably, the water-based lubricating and wear-resistant agent is polydimethylsiloxane or polyphenylmethylsiloxane.

[0023] Furthermore, the curing agent mentioned above is a low-volatility aliphatic polyisocyanate with an isocyanate group value of 20-30%;

[0024] By selecting a suitable curing agent, the adhesion between molecules of the hydroxyacrylic acid copolymer dispersion can be improved, thereby enhancing the stability of the release film under extreme conditions. Preferably, the isocyanate group value is 22-28%, more preferably 24-27%;

[0025] Furthermore, the aqueous drying agent is butyl acrylate or isobutyl acrylate.

[0026] By selecting a suitable water-based drying agent, the drying speed during the production of release film can be accelerated, enabling the product to be produced on coating machines or printing machines with shorter drying tunnels, thus improving the product's compatibility with equipment. It can also undergo copolymerization with hydroxy acrylic acid copolymer dispersions at a temperature of 70-90℃ in the drying tunnel, thereby improving the mechanical properties of the release film.

[0027] In a second aspect, this application provides an environmentally friendly waterborne release film, which includes a substrate and a release layer located on at least one side of the substrate, the release layer including an adhesion layer and a curing layer, and is made of an environmentally friendly waterborne release agent as described in the first aspect of this application;

[0028] The adhesion layer is formed by coating the modified acrylic resin onto the surface of the substrate and then drying it; the curing layer is formed by mixing and stirring the raw materials of the coating composition and then coating them onto the adhesion layer.

[0029] Thirdly, this application provides a method for implementing the above-mentioned environmentally friendly aqueous release membrane, comprising:

[0030] (1) After mixing and stirring the self-crosslinking acrylic resin and the acrylate copolymer, an antioxidant is added and the mixture is stirred evenly to obtain a modified acrylic resin. The modified acrylic resin is then coated onto a substrate to form an adhesion layer.

[0031] (2) The hydroxy acrylic copolymer dispersion, water-based lubricating and wear-resistant agent, curing agent, water-based drying agent and deionized water are mixed evenly to obtain a coating liquid. The coating liquid is then applied to the surface of the adhesion layer to form a cured layer.

[0032] In the above-mentioned technical solution, the water-based release film is first applied as a primer to the substrate surface to form an adhesion layer, which helps to improve the adhesion of the coating on the release film surface. After the adhesion layer dries, a coating liquid formed by mixing specific components and proportions is applied to its surface, and after curing, an environmentally friendly water-based release film is formed.

[0033] In summary, this application has the following beneficial effects:

[0034] The environmentally friendly waterborne release agent provided in this application is composed of a modified acrylic resin and a coating composition used in combination. The hydroxyl acrylic copolymer dispersion in the coating composition acts as a two-component waterborne varnish, enabling the base film to achieve a release effect. By combining the hydroxyl acrylic copolymer dispersion with other waterborne components (such as waterborne slip-enhancing and abrasion-resistant agents, and waterborne drying agents), the release film does not generate large amounts of volatile organic compounds during production, making it pollution-free and environmentally friendly, and significantly reducing production costs. Simultaneously, by modifying the acrylic resin and combining it with the hydroxyl acrylic copolymer dispersion, the surface strength and stability of the release film can be increased.

[0035] In the process of modifying acrylic resin, self-crosslinking acrylic resin and acrylate copolymer are mixed and stirred. The combination of the two causes the molecular chains to expand at the molecular level, forming a network structure, which enhances the connection strength between small molecules and thus improves the surface firmness of the release film.

[0036] The environmentally friendly waterborne release film provided in this application uses a modified acrylic resin as a primer, which improves the adhesion of the coating on the release film surface. The release film can be applied simply by mixing and then using a printing press. The resulting environmentally friendly waterborne release film meets the standards of existing silicone release films in terms of peel strength, adhesion, and stability, while significantly reducing production costs and requiring only the treatment of a very small amount of VOC emissions. Attached Figure Description

[0037] Figure 1 is a photograph of the preparation process of the environmentally friendly aqueous release membrane provided in this application;

[0038] Figure 2 is a photograph of the preparation process of the environmentally friendly aqueous release membrane provided in this application; Detailed Implementation

[0039] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0040] The raw materials and their sources used in the embodiments of this application are shown in Table 1:

[0041] Table 1. Some raw materials and their sources

[0042] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0043] Example of raw material preparation

[0044] Preparation Examples 1-6

[0045] Preparation Examples 1-6 each provide a modified acrylic resin, which is prepared as follows: the self-crosslinking acrylic resin and the acrylate copolymer are poured into a mixing container and stirred with a stirrer at 30-40 revolutions per minute for 10-15 minutes to make it fully mixed. Then, it is placed under normal atmospheric pressure and a temperature of 5-30 degrees Celsius and left to stand for 24 hours.

[0046] The antioxidant was added to the mixture of self-crosslinking acrylic resin and acrylate copolymer, and stirred with a mixer at 20-30 rpm for 5-10 minutes to ensure thorough mixing and obtain the modified acrylic resin. The raw material formulations for the modified acrylic resins in Examples 1-6 are shown in Table 2.

[0047] Table 2. Raw material ratios for the modified acrylic resins in Examples 1-6

[0048] Comparative Preparation Examples 1-2

[0049] The preparation methods of Comparative Preparation Examples 1-2 are basically the same as those of Preparation Example 1, except that the raw material ratio is adjusted and the preparation of the mixture of crosslinked acrylic resin and acrylate copolymer is omitted. The antioxidant is directly poured into the self-crosslinked acrylic resin or acrylate copolymer, as shown in Table 3.

[0050] Table 3. Raw material ratios of the modified acrylic resins in Comparative Preparation Examples 1-2

[0051] Example

[0052] First set of embodiments

[0053] This set of embodiments provides an environmentally friendly waterborne release film, which includes a substrate and a release layer located on at least one side of the substrate, the release layer including an adhesion layer and a curing layer;

[0054] Preparation methods include:

[0055] (1) Material preparation: Prepare materials according to the raw materials shown in Table 4, and use polyethylene film as the substrate.

[0056] (2) Applying the adhesion layer: The modified acrylic resin obtained in Preparation Example 2 was diluted with deionized water to a suitable viscosity, coated onto the substrate, and dried;

[0057] (3) Applying the curing layer: Pour the water-based slip-enhancing and wear-resistant agent, curing agent, water-based drying agent, and deionized water into a mixing container, and stir with a stirrer at 10 rpm for 5-10 minutes to ensure uniform mixing. Then, slowly pour in the hydroxyl acrylic copolymer dispersion, increase the speed to 10-20 rpm, and stir for 5-10 minutes to obtain the coating liquid. Then, apply the coating liquid to the surface of the adhesion layer using a coating machine or printing machine, and dry it in an oven at 70-90℃ to obtain an environmentally friendly water-based release film. The raw material formulation of the water-based release film in this set of examples is shown in Table 4.

[0058] Table 4. Raw material ratio of water-based release film

[0059] The curing agent is a low-volatility aliphatic polyisocyanate with an isocyanate group value of 24%; the water-based drying agent is butyl acrylate; and the water-based lubricating and wear-resistant agent is polydimethylsiloxane.

[0060] Second set of embodiments

[0061] The raw material ratios in this set of examples are basically the same as those in Example 2, except that this set of examples uses modified acrylic resins provided in different preparation examples, as shown in Table 5:

[0062] Table 5. Raw material ratio of water-based release film

[0063] Example 13

[0064] This embodiment provides an environmentally friendly aqueous release membrane, the preparation method of which is basically the same as that in Example 2, the difference being the selection of raw materials, as shown in Table 6:

[0065] Table 6. Composition and Proportion of Raw Materials

[0066] Example 14

[0067] This embodiment provides an environmentally friendly aqueous release membrane, the preparation method of which is basically the same as that in Example 2, the difference being the selection of raw materials, as shown in Table 7:

[0068] Table 7. Composition and Proportion of Raw Materials

[0069] Example 15

[0070] This embodiment provides an environmentally friendly aqueous release membrane, the preparation method of which is basically the same as that of Example 2, except for the selection and proportioning of raw materials, as shown in Table 8:

[0071] Table 8. Composition and Proportion of Raw Materials

[0072] Comparative Example

[0073] Comparative Examples 1-6

[0074] The preparation methods of Comparative Examples 1-6 are basically the same as those of the first set of examples, except for the selection and proportioning of raw materials, as shown in Table 9:

[0075] Table 9. Selection and Proportioning of Raw Materials

[0076] The curing agent is a low-volatility aliphatic polyisocyanate with an isocyanate group value of 24%; the water-based drying agent is butyl acrylate; and the water-based lubricating and wear-resistant agent is polydimethylsiloxane.

[0077] Performance testing

[0078] I. Detection Methods

[0079] The performance parameters of the aqueous release films prepared in Examples 1-7 and Comparative Examples 1-6 were determined using the following methods.

[0080] Peel force determination of release film

[0081] The test standard GB / T27731 requires a peel strength of <0.45 N / 25 mm at 180°C for 20 min.

[0082] Determination of residual adhesion of release film

[0083] Test standard GB / T27731 requires residual tack to be ≥90%.

[0084] Stability determination of release film

[0085] The test standard GB / T27731 requires a peel strength of <0.6 N / 25 mm at 70°C aging and 180°C at room temperature (24h).

[0086] Surface dynamic friction force measurement of release film

[0087] The test standard GB / T1006 requires the coefficient of dynamic friction (COF) of uncoated surfaces to be >0.35.

[0088] II. Test Results

[0089] The test results are shown in Table 10:

[0090] Table 10. Performance Test Results

[0091] As shown in Table 10, the release agents provided in Examples 1-7 of this application all exhibit excellent peel strength, residual adhesion, stability, and surface dynamic friction coefficient, meeting the standards of existing silicone release films, while significantly reducing VOC emissions during the production process. Among them, Example 2 shows the best performance.

[0092] Comparing Example 2 with Comparative Examples 1-4 reveals that the modification method and content of the modified acrylic resin have a significant impact on the peel strength and stability of the release film. When no self-crosslinking acrylic resin is added to the modified acrylic resin (Comparative Example 2), the residual tack and stability of the release film are significantly reduced. Similarly, when no acrylate copolymer is added to the modified acrylic resin (Comparative Example 1), the release film also exhibits reduced residual tack and stability. This is mainly because the self-crosslinking acrylic resin and the acrylate copolymer can cause the molecular chains to expand at the molecular level, forming a network structure and enhancing the connection strength between small molecules. Furthermore, excessive or insufficient addition of the modified acrylic resin (Comparative Examples 3-4) also affects the peel strength, residual tack, and stability of the release film.

[0093] Comparing Example 2 with Comparative Examples 5-6, it can be found that when the content of hydroxyacrylic acid copolymer dispersion is too high or too low (Comparative Examples 5-6), the COF performance of the release film is poor.

[0094] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An environmentally friendly water-based release agent, characterized in that, It includes modified acrylic resins and coating compositions used in combination; The raw materials for the modified acrylic resin include: self-crosslinking acrylic resin, acrylate copolymer, and antioxidant; The raw materials of the coating composition include hydroxy acrylic copolymer dispersion, water-based slip and wear-resistant agent, curing agent, water-based drying agent and deionized water; The mass ratio of the modified acrylic resin to the coating composition is (75-104):(40-60).

2. The environmentally friendly water-based release agent according to claim 1, characterized in that, The raw materials for the modified acrylic resin include, by weight parts: 30-50 parts of self-crosslinking acrylic resin, 1-4 parts of acrylate copolymer, and 1-3 parts of antioxidant.

3. The environmentally friendly water-based release agent according to claim 2, characterized in that, The modified acrylic resin is obtained by the following method: According to the weight parts, the self-crosslinking acrylic resin and the acrylate copolymer are mixed and stirred evenly, and then the antioxidant is added and mixed.

4. The environmentally friendly water-based release agent according to claim 1, characterized in that, The coating composition comprises, by weight parts: 70-90 parts of hydroxyl acrylic acid copolymer dispersion; 1-3 parts of water-based lubricating and wear-resistant agent; 1-3 parts of curing agent; 1-5 parts of water-based drying agent; 1-3 parts of water.

5. The environmentally friendly water-based release agent according to claim 4, characterized in that, The water-based lubricating and wear-resistant agent includes any one of polydimethylsiloxane, polyphenylmethylsiloxane, and polyether-modified polydimethylsiloxane.

6. The environmentally friendly water-based release agent according to claim 4, characterized in that, The curing agent is a low-volatility aliphatic polyisocyanate with an isocyanate group value of 20-30%.

7. The environmentally friendly water-based release agent according to claim 4, characterized in that, The aqueous drying agent is butyl acrylate or isobutyl acrylate.

8. An environmentally friendly waterborne release membrane, characterized in that, It includes a substrate and a release layer located on at least one side of the substrate, the release layer including an adhesion layer and a curing layer, and is made of an environmentally friendly water-based release agent as described in any one of claims 1-7; The adhesion layer is formed by coating the modified acrylic resin onto the surface of the substrate and then drying it; the curing layer is formed by mixing and stirring the raw materials of the coating composition and then coating them onto the adhesion layer.

9. A method for implementing the environmentally friendly waterborne release membrane as described in claim 8, characterized in that, It includes: After mixing and stirring the self-crosslinking acrylic resin and the acrylate copolymer, an antioxidant is added and the mixture is stirred evenly to obtain a modified acrylic resin. The modified acrylic resin is then coated onto a substrate to form an adhesion layer. The hydroxy acrylic copolymer dispersion, water-based slip and wear-resistant agent, curing agent, water-based drying agent and deionized water are then mixed evenly to obtain a coating liquid. The coating liquid is then applied to the surface of the adhesion layer to form a cured layer.

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