Environment-friendly decorative paper as well as preparation method and application thereof

Abstract

The invention relates to the technical field of packaging paper, and discloses environment-friendly decorative paper and a preparation method and application thereof.The environment-friendly decorative paper comprises a base material, and an EB functional layer is formed on the base material; the EB functional layer is a coating layer formed by curing a functional coating through EB radiation curing; the functional coating is prepared from polyurethane and acrylic resin in a weight ratio of (1: 1)-(1: 4). According to the preparation method, the EB functional layer is prepared on the base material through the EB curing technology to replace a traditional high-temperature curing technology, the energy consumption problem of high-temperature curing can be avoided, and the preparation process of the EB functional layer is efficient. Besides, a formaldehyde-free environment-friendly process is realized, and an EB curing technology is combined, so that good bonding force can be formed between the EB functional layer and a base material, the EB functional layer has excellent wear resistance, scratch resistance and ultraviolet resistance, the service life of the decorative paper can be effectively prolonged, and the decorative paper is particularly remarkable in outdoor or high-use-frequency application.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging paper, and in particular to an environmentally friendly decorative paper and a preparation method and application thereof. Background Art

[0002] Decorative paper is a new type of artificial board veneer material with the characteristics of easy processing and good decorative effect. At present, the main decorative paper is obtained by printing decorative base paper and dipping it in melamine resin. Due to its low price, melamine paper is widely used in furniture, flooring and other fields, but melamine paper usually needs to be cured with resin containing formaldehyde, and long-term use may have a negative impact on the environment and human health. In addition, the color saturation and stability of melamine paper will decrease after long-term use due to its susceptibility to light and environmental influences, resulting in limited durability.

[0003] In order to minimize formaldehyde emissions, related companies use organic emulsion compounds such as water-based polyurethane and water-based acrylate as impregnating adhesives to prepare pre-impregnated paper to replace traditional melamine-formaldehyde resins. Based on the excellent properties of polyurethane and acrylic resins, these materials provide good flexibility and durability in decorative paper. However, the traditional thermal curing process is energy-intensive and has low production efficiency, which makes it difficult to meet the modern industry's demand for high efficiency and environmental protection. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an environmentally friendly decorative paper and a preparation method and application thereof, which can avoid the energy consumption problem of high-temperature curing and is efficient and environmentally friendly, and the color saturation and stability of the decorative paper can be improved.

[0005] In order to solve the above technical problems, the present invention provides an environmentally friendly decorative paper in a first aspect, comprising a substrate, an EB functional layer being formed on the substrate;

[0006] The EB functional layer is a coating layer formed by curing the functional coating using EB radiation curing;

[0007] The raw materials for preparing the functional coating include polyurethane and acrylic resin, and the weight ratio of the polyurethane and acrylic resin is 1:1 to 1:4.

[0008] As an improvement of the above solution, the coating thickness of the EB functional layer is 20 μm-30 μm.

[0009] As an improvement of the above scheme, the raw materials for preparing the functional coating include, by weight:

[0010] 10 - 30 parts of polyurethane, 15 - 40 parts of acrylic resin, 20 - 60 parts of prepolymer, 1 - 5 parts of crosslinking agent, 5 - 15 parts of reactive diluent, 0.5 - 5 parts of penetration enhancer, 1 - 5 parts of pigment filler, 0 - 15 parts of auxiliary agent.

[0011] As an improvement of the above - mentioned scheme, the acrylic resin is a soft acrylic resin;

[0012] The polyurethane selected is water - borne polyurethane;

[0013] The prepolymer selected is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyacrylate, and polyether acrylate.

[0014] As an improvement of the above - mentioned scheme, the reactive diluent is a bifunctional acrylate monomer, and the bifunctional acrylate monomer is selected from one or more of tripropylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4 - butanediol dimethacrylate, neopentyl glycol dimethacrylate, and neopentyl glycol dipropoxy dimethacrylate.

[0015] As an improvement of the above - mentioned scheme, the crosslinking agent is selected from one or more of aziridine, cyclohexylamine, and epoxy compounds;

[0016] The penetration enhancer is selected from one or more of span, tween, ethyl ethyl ether, and fatty acid polyethylene ether.

[0017] As an improvement of the above - mentioned scheme, the voltage for EB radiation curing is 100 - 150 kV, the irradiation dose is 20 kGy - 90 kGy, and the oxygen content is 110 - 500 ppm.

[0018] As an improvement of the above - mentioned scheme, the substrate is selected from one of prepreg paper and raw base paper.

[0019] The second aspect of the present invention provides a preparation method of the environmentally friendly decorative paper as described above, including:

[0020] Providing a substrate;

[0021] Providing a functional coating;

[0022] Coating the functional coating on the surface of the substrate, and then curing the functional coating coated on the surface of the substrate by EB curing technology to form an EB functional layer, thus obtaining the environmentally friendly decorative paper.

[0023] The third aspect of the present invention provides an application of the environmentally friendly decorative paper as described above, which is used for decorating furniture, floors, and building materials.

[0024] Implementing the present invention has the following beneficial effects:

[0025] (1) The raw materials for preparing the functional coating in the present invention include polyurethane and acrylic resin. Compared with the traditional melamine resin, the EB functional layer does not contain formaldehyde and other volatile organic compounds (VOCs), realizing a completely formaldehyde-free environmental protection process, meeting the requirements of green building materials and environmental protection certifications, and satisfying the increasingly strict environmental protection regulations and market demands. It is especially suitable for indoor use or application scenarios with high environmental protection requirements.

[0026] (2) The EB functional layer in the present invention is a coating layer formed by curing the functional coating using EB radiation curing. Compared with the traditional thermal curing process, it significantly shortens the production cycle, and the curing process does not require high temperature, reducing energy consumption and improving production efficiency.

[0027] (3) In the present invention, the EB cured coating has high adhesion on the substrate, and the EB cured coating has excellent wear resistance, scratch resistance and ultraviolet resistance, which can effectively extend the service life of the decorative paper, especially remarkable in outdoor or applications with high usage frequency.

[0028] (4) The EB curing process can flexibly adjust the coating thickness, pigment types and resin combinations, providing diverse customization solutions to meet the requirements of different customers for the flexibility, gloss and other properties of the decorative paper, making it more suitable for the decoration of furniture, floors and building materials. Specific embodiments

[0029] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail with specific embodiments below.

[0030] To solve the above problems, the first aspect of the present invention provides an environmentally friendly decorative paper, including a substrate, on which an EB functional layer is formed;

[0031] The EB functional layer is a coating layer formed by curing the functional coating using EB radiation curing;

[0032] The raw materials for preparing the functional coating include polyurethane and acrylic resin.

[0033] In the present invention, the EB functional layer is prepared on the substrate by EB curing technology to replace the traditional high temperature curing process, which can not only avoid the energy consumption problem of high temperature curing, but also the preparation process of the EB functional layer is efficient. In addition, the functional coating containing polyurethane and acrylic resin is used for curing, and there is no need to use materials containing formaldehyde or other volatile organic compounds (VOCs), so that a formaldehyde-free environmentally friendly process is achieved, which meets the requirements of green building materials and environmental protection certification, and is particularly suitable for indoor use or application scenarios with high environmental protection requirements. At the same time, combined with EB curing technology, a good bonding force can be formed between the EB functional layer and the substrate, and the EB functional layer has excellent wear resistance, scratch resistance and UV resistance, which can effectively extend the service life of the decorative paper, which is particularly significant in outdoor or high-frequency applications.

[0034] Preferably, the raw materials for preparing the functional coating include, by weight, 10-30 parts of polyurethane, 15-40 parts of acrylic resin, 20-60 parts of prepolymer, 1-5 parts of crosslinking agent, 5-15 parts of active diluent, 0.5-5 parts of penetration enhancer, 1-5 parts of pigment and filler, and 0-15 parts of additive. The system of polyurethane, acrylic resin, and prepolymer is selected as the functional coating, and combined with the use of EB curing technology, the pigment and filler can be firmly embedded in the coating during the EB curing process to prevent fading or color migration, and produce a colorful and stable decorative paper suitable for applications exposed to light or harsh environments for a long time. In addition, the use of photoinitiators is avoided, which can well avoid the problems of oxidation yellowing and poor stability of the coating.

[0035] Replacing the traditional melamine system with polyurethane and acrylic resin has the problem of poor permeability on the substrate. Therefore, waterborne polyurethane resin is selected for polyurethane, and soft acrylic resin is selected for acrylic resin. Collaborating with prepolymers, crosslinking agents, reactive diluents, and penetration promoters can provide excellent flexibility, wear resistance, and weather resistance for the EB functional layer, thereby improving the overall performance of the decorative paper. Among them, the waterborne polyurethane resin has a relatively small viscosity and good compatibility with the components in the functional coating, which is convenient for the uniform coating of the functional coating, and it has better weather resistance and corrosion resistance, which can better improve the mechanical properties and stability of the EB functional layer. Compared with hard acrylic resin, soft acrylic resin has high flexibility, which helps to improve the flexibility, elasticity, and adhesion of acrylic resin, promotes the adhesion of the functional coating on the substrate, and improves the wettability of the functional coating to pigments and fillers, meeting the decorative effects for furniture, floorboards, and building materials. Further, the waterborne polyurethane is aliphatic polyurethane, with a viscosity of 15 s - 50 s and an elongation at break of 500% - 700%. It should not be ignored that the hardness, wear resistance, impact resistance, and weather resistance of soft acrylic resin are slightly inferior to those of hard acrylic resin. When EB curing is carried out, the electron beam may penetrate the functional coating and cause chemical structure changes on its surface, enabling it to have chemical bond interactions with the substrate, enhancing the adhesion of the functional coating to the substrate, forming a higher-density three-dimensional crosslinked network structure, and achieving a higher degree of curing of the polymer, largely making up for these defects. If hard acrylic resin is directly selected, it will lead to a decrease in the adhesion of the coating to the substrate, increasing the risk of the cured coating peeling off from the substrate.

[0036] In some specific and preferred embodiments, the solid content of the soft acrylic resin is ≥95%, the glass transition temperature (Tg) is -50°C - -20°C, and the viscosity at 23°C and 25 s is 150 mPa·s - 200 mPa·s. It can not only exhibit good adhesion and flexibility but also improve the fluidity and leveling property of the functional coating on the substrate, forming a stable functional protective layer.

[0037] Further, a penetration promoter can be added to the system to enable the functional coating to penetrate into the interior of the substrate, further improving the comprehensive strength of the EB functional layer, such as impact resistance, wear resistance, etc. The penetration promoter can use common paper penetration agents, preferably safe and non-toxic penetration agents. Exemplarily, the penetration promoter is span, tween, ethyl ethyl ether, fatty acid polyethylene ether, etc.

[0038] Furthermore, to enable the polyurethane and acrylic resin to form a stable structure under the action of electron beam, a crosslinking agent is added to the system to promote the crosslinking polymerization of polyurethane and acrylic resin. Optionally, the crosslinking agent is selected from one or more of aziridine, cyclohexylamine, and epoxy compounds.

[0039] Preferably, the prepolymer is an oligomer containing double bonds, and the prepolymer is selected from one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyacrylate, and polyether acrylate.

[0040] Further, the weight ratio of the polyurethane to the acrylic resin added is 1:1 to 1:4, ensuring that the EB functional layer has excellent hardness and fluidity, forming a uniform and stable-performance EB functional layer on the substrate surface, showing better protection and decorative effects; more preferably, the weight ratio of the polyurethane to the acrylic resin added is 1:1 to 1:3.

[0041] Preferably, the reactive diluent can improve the viscosity of the system and participate in the cross-linking reaction among the polyurethane, acrylic resin, and prepolymer. The reactive diluent can be an acrylate monomer containing double bonds. The acrylate monomers include monofunctional acrylate monomers, difunctional acrylate monomers, and polyfunctional acrylate monomers. Optionally, the reactive diluent is a difunctional acrylate monomer, and the difunctional acrylate monomer is selected from one or more of neopentyl glycol diacrylate, hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol dipropoxy diacrylate, neopentyl glycol dipropoxy dimethacrylate, 2-methyl-1,3-propanediol diacrylate; more preferably, the difunctional acrylate monomer is selected from one or more of tripropylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, neopentyl glycol dipropoxy dimethacrylate. The methacrylate monomer, when mixed with the prepolymer and acrylic resin, can have higher cross-linking activity under the action of electron beam, obtaining a higher cross-linking density, further improving the hardness, wear resistance, scratch resistance, and leveling performance of the EB functional layer, and thus extending the service life of the decorative paper.

[0042] Preferably, the pigment and filler can be uniformly dispersed in the system. Using EB curing technology can ensure rich and stable colors and excellent light stability. The pigment and filler are inorganic pigments or organic pigments, and can be specifically adjusted flexibly to meet the different needs of different customers, and are not specifically limited in the present invention.

[0043] Further, the coating thickness of the EB functional layer is 20 μm - 30 μm, which can ensure the smoothness and uniformity of the functional coating, enabling the decorative paper to exhibit excellent physical properties such as hardness, while further presenting the color of the pigment and filler, and enhancing the decorative effect of the decorative paper. The voltage for EB radiation curing is 100 - 150 kV, the irradiation dose is 20 kGy - 90 kGy, and the oxygen content is 110 - 500 ppm. By controlling the energy and other factors during the EB radiation curing process, it can ensure the full combination of the functional coating and the substrate. Moreover, the synergistic effect of multiple conditions such as voltage, dose, and oxygen content can also ensure that the obtained EB layer has excellent abrasion resistance, scratch resistance, and high hardness within the shortest possible curing time, avoiding the generation of more oxidized groups during the curing process, which may lead to a decrease in the long-term stability and weather resistance of the obtained EB layer. By adjusting the EB curing process, the thickness of the functional layer, the types of pigments, and the resin combination can be flexibly adjusted to provide diverse customization options to meet the requirements of different customers for the flexibility, gloss, and other properties of the decorative paper.

[0044] In some embodiments, the additives include, but are not limited to, one of wear-resistant fillers, ultraviolet absorbers, flame retardants, antibacterial agents, leveling agents, dispersants, heat stabilizers, antioxidants, and water repellents. The additives can be reasonably added or adjusted according to the actual situation.

[0045] Correspondingly, the present invention provides a method for preparing an environmentally friendly decorative paper, comprising:

[0046] (1) Providing a substrate;

[0047] The substrate is selected from one of prepreg paper and raw blank paper base. The prepreg paper can be a decorative paper treated with resin materials and reinforcing materials such as fibers.

[0048] (2) Providing a functional coating;

[0049] The raw materials for preparing the functional coating, by weight, include: 10 - 30 parts of polyurethane, 15 - 40 parts of acrylic resin, 20 - 60 parts of prepolymer, 1 - 5 parts of crosslinking agent, 5 - 15 parts of reactive diluent, 0.5 - 5 parts of penetration promoter, 1 - 5 parts of pigment and filler, and 0 - 15 parts of additives.

[0050] (3) Coating the functional coating on the surface of the substrate, and then using EB curing technology to cure the functional coating coated on the surface of the substrate to form an EB functional layer, thereby obtaining the environmentally friendly decorative paper.

[0051] Preferably, the functional coating can be applied by a coating process, which can be conventional methods such as direct coating, spraying, roll coating, knife coating, etc. In the present invention, the functional coating is applied by direct coating, and the functional coating is directly coated on the surface of the substrate. Subsequently, radiation curing by EB curing technology can effectively avoid delamination or peeling of the EB layer on the substrate layer, improve the yield rate, and improve production efficiency and save costs.

[0052] Furthermore, the preparation method further includes post-treatment, and the post-treatment includes directly winding or cutting the cured decorative paper to form a finished product for furniture, floor or other covering materials.

[0053] Correspondingly, the present invention also provides an application of the environmentally friendly decorative paper described above, which is used to decorate furniture, floors, and building materials.

[0054] The following further illustrates the present invention with specific examples:

[0055] Example 1

[0056] This example provides an environmentally friendly decorative paper, including a raw blank paper base, and an EB functional layer is formed on the raw blank paper base.

[0057] The EB functional layer is a coating layer formed by curing a functional coating by EB radiation curing, and the thickness of the EB functional layer is 20 μm.

[0058] The preparation raw materials of the functional coating include, by weight:

[0059] 20 parts of polyurethane, 30 parts of acrylic resin, 40 parts of prepolymer, 2 parts of crosslinking agent, 12 parts of reactive diluent, 1 part of penetration enhancer, and 2 parts of pigment filler.

[0060] Among them, the polyurethane is purchased from Shandong Haozun Biotechnology Co., Ltd., HZRU 6222, the acrylic resin is purchased from Mitsubishi of Japan, MB-2952, the prepolymer is epoxy acrylate, the crosslinking agent is cyclohexylamine, the reactive diluent is triethylene glycol dimethacrylate and 1,4-butanediol dimethacrylate with a weight ratio of 1:1, the penetration enhancer is ethyl ethyl ether, and the pigment filler is inorganic pigment.

[0061] This example also provides a preparation method of an environmentally friendly decorative paper, including:

[0062] Formulate according to the ratio of the preparation raw materials to obtain a functional coating; then evenly apply the functional coating on the surface of the raw blank paper base through a coating device, and perform curing treatment with an electron beam curing device, with a voltage of 125 kV, an irradiation dose of 55 kGy, and an oxygen content of 280 ppm.

[0063] Example 2

[0064] This embodiment provides an environmentally friendly decorative paper, which is basically the same as Embodiment 1, except that:

[0065] The polyurethane is waterborne polyurethane, and the waterborne polyurethane is aliphatic polyurethane with a viscosity of 20 s ± 50 s, an elongation at break of 600% (Wengkel, H-34A), the solid content of the acrylic resin is ≥98.5%, the glass transition temperature (TG) is -40 °C, and the viscosity in 50% ethyl acetate at 23 °C and 25 s is 165 mPa·s (BASF, Acronal 4F).

[0066] Embodiment 3

[0067] This embodiment provides an environmentally friendly decorative paper, which is basically the same as Embodiment 1, except that:

[0068] The thickness of the EB functional layer is 30 μm.

[0069] The voltage is 140 kV, the irradiation dose is 65 kGy, and the oxygen content is 400 ppm.

[0070] Embodiment 4

[0071] This embodiment provides an environmentally friendly decorative paper, which is basically the same as Embodiment 2, except that:

[0072] The raw materials for preparing the functional coating include, by weight:

[0073] 20 parts of waterborne polyurethane, 15 parts of acrylic resin, 60 parts of prepolymer, 2 parts of crosslinking agent, 12 parts of reactive diluent, 1 part of penetration enhancer, and 2 parts of pigment and filler.

[0074] Embodiment 5

[0075] This embodiment provides an environmentally friendly decorative paper, which is basically the same as Embodiment 2, except that:

[0076] The reactive diluent is hexanediol diacrylate and 1,4-butanediol dimethacrylate with a weight ratio of 1:1.

[0077] Comparative Example 1

[0078] This comparative example provides an environmentally friendly decorative paper, which is basically the same as Embodiment 1, except that:

[0079] The raw materials for preparing the functional coating include, by weight:

[0080] 20 parts of polyurethane, 40 parts of prepolymer, 2 parts of crosslinking agent, 12 parts of reactive diluent, 1 part of penetration enhancer, and 2 parts of pigment and filler.

[0081] Comparative Example 2

[0082] This comparative example provides an environmentally friendly decorative paper, which is basically the same as Example 1, except that:

[0083] A functional layer is formed on the base material;

[0084] The functional layer is a coating layer formed by curing a functional coating by high-temperature heating and curing. The curing temperature is 120°C and the curing time is 5 minutes.

[0085] Performance test:

[0086] The following tests are carried out on the environmentally friendly decorative papers obtained in the examples and comparative examples, specifically as follows:

[0087] 1. Hardness: Measured according to GB / T 6739-2022 "Determination of film hardness by pencil method for paints and varnishes".

[0088] 2. Adhesion: Measured according to GB / T 9286-1998 "Cross-cut test for paints and varnishes films".

[0089] 3. Color saturation: The color difference value of the sample at the initial time and the color difference value after cyclic exposure treatment are measured according to GB / T 11942-2022, where the cyclic exposure is carried out according to item 2 in Table 4 of GB / T 16422.3.

[0090] The test results are shown in Table 1.

[0091] Table 1 Performance test results of examples and comparative examples

[0092]

[0093]

[0094] It can be seen from the above results that compared with the environmentally friendly decorative paper prepared by the high-temperature curing method, the EB functional layer prepared by EB curing in the present invention has high adhesion on the base material, and can well improve the wear resistance, scratch resistance and ultraviolet resistance of the environmentally friendly decorative paper, effectively extending the service life of the decorative paper, which is particularly significant in outdoor or high-usage applications. At the same time, compared with the traditional thermal curing process, the production cycle is greatly shortened, and the curing process does not require high temperature, reducing energy consumption and improving production efficiency. It realizes a completely formaldehyde-free environmental protection process, meeting the requirements of green building materials and environmental protection certification.

[0095] The above-disclosed is only a preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. An environmentally friendly decorative paper, characterized in that, It includes a substrate, on which an EB functional layer is formed; The EB functional layer is a coating layer formed by curing a functional coating through EB radiation curing; The preparation raw materials of the functional coating include polyurethane and acrylic resin, and the weight ratio of the added polyurethane and acrylic resin is 1:1 to 1:

4.

2. The environmentally friendly decorative paper according to claim 1, characterized in that The coating thickness of the EB functional layer is 20μm - 30μm.

3. The environmentally friendly decorative paper according to claim 1, wherein The preparation raw materials of the functional coating, by weight, include: 10 - 30 parts of polyurethane, 15 - 40 parts of acrylic resin, 20 - 60 parts of prepolymer, 1 - 5 parts of crosslinking agent, 5 - 15 parts of reactive diluent, 0.5 - 5 parts of penetration enhancer, 1 - 5 parts of pigment extender, and 0 - 15 parts of auxiliary agent.

4. The environmentally friendly decorative paper according to claim 3, characterized in that, The acrylic resin is a soft acrylic resin; The polyurethane is selected from waterborne polyurethanes; The prepolymer is selected from one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyacrylate, and polyether acrylate.

5. The environmentally friendly decorative paper according to claim 3, characterized in that, The reactive diluent is a bifunctional acrylate monomer, and the bifunctional acrylate monomer is selected from one or more of tripropylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,4 - butanediol dimethacrylate, neopentyl glycol dimethacrylate, and neopentyl glycol dipropoxy dimethacrylate.

6. The environmentally friendly decorative paper according to claim 4 or 5, characterized in that, The crosslinking agent is selected from one or more of aziridine, cyclohexylamine, and epoxy compounds; The penetration enhancer is selected from one or more of span, tween, ethyl ethyl ether, and fatty acid polyethylene ether.

7. The environmentally friendly decorative paper according to any one of claims 1-5, characterized in that, The voltage of the EB radiation curing is 100 - 150 kV, the irradiation dose is 20 kGy - 90 kGy, and the oxygen content is 110 - 500 ppm.

8. The environmentally friendly decorative paper according to claim 1, characterized in that, The substrate is selected from one of prepreg paper and raw base paper.

9. A method for preparing the environmentally friendly decorative paper according to any one of claims 1-8, characterized in that, It includes: Providing a substrate; Providing a functional coating; Coating the functional coating on the surface of the substrate, and then curing the functional coating coated on the surface of the substrate by using EB curing technology to form an EB functional layer, thereby obtaining the environmental protection decorative paper.

10. Use of an environment-friendly decorative paper according to any one of claims 1-8, characterized in that, It is used for decorating furniture, floors, and building materials.

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