CN113172973A

CN113172973A - Leather filling paper

Info

Publication number: CN113172973A
Application number: CN202110379819.3A
Authority: CN
Inventors: 李民; 李庆北; 蔡相成
Original assignee: Shanghai HIUV Applied Materials Technology Co Ltd; Shanghai HIUV New Materials Co Ltd
Current assignee: Shanghai HIUV Applied Materials Technology Co Ltd; Shanghai HIUV New Materials Co Ltd
Priority date: 2021-04-08
Filing date: 2021-04-08
Publication date: 2021-07-27

Abstract

The invention provides leather-filled paper. The leatherette paper comprises: paper base; the polyolefin layer is laminated on the surface of the paper base, the ingredients of the polyolefin layer comprise 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight, and the crosslinking degree of the polyolefin layer is 1-95%; a polyurethane layer laminated to the surface of the polyolefin layer facing away from the paper substrate. The leather-filled paper provided by the invention has the advantages of low odor and good embossability.

Description

Leather filling paper

Technical Field

The invention belongs to the technical field of packaging materials, and particularly relates to leather filling paper.

Background

The leather-filled paper is formed by attaching a resin layer on the surface of a paper base. Because of its flexibility and leather feel, it is widely used as a packaging material.

The leather-filled paper can be classified according to material, and can comprise polyvinyl chloride (PVC) leather-filled paper, Polyurethane (PU) leather-filled paper, ethylene-vinyl acetate copolymer (EVA) leather-filled paper and the like. The PVC leatherette paper is easy to generate undesirable odor due to the plasticizer, and the PVC material is difficult to degrade; meanwhile, PVC contains halogen, so that the PVC is difficult to meet high-end environmental protection requirements and is usually used as a low-end product. The EVA leatherette paper has obvious acetic acid taste, and is difficult to be applied to the field with higher requirements on smell. The existing PU leatherette paper usually uses a large amount of organic solvents (such as dimethylformamide, methyl ethyl ketone, acetone, toluene, ethyl acetate and the like), so that the problems of poor odor and low environmental protection property exist. Moreover, most PU leather-filled paper in the existing market forms relatively shallow grains in a veneering transfer mode, and the leather-filled paper with deeper grains cannot be produced; the self paper base of the PU leatherette paper obtained by embossing is forced to deform, so that the flexibility and the strength of the PU leatherette paper are greatly reduced, and the requirement of actual physical properties cannot be met; the PU leatherette paper also has the disadvantage of being relatively expensive.

Therefore, it is important to find a leatherette paper having a low odor property and a good embossability.

Disclosure of Invention

In order to solve the above technical problem, the present invention provides a leatherette paper, comprising: paper base; the polyolefin layer is laminated on the surface of the paper base, the ingredients of the polyolefin layer comprise 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight, and the crosslinking degree of the polyolefin layer is 1-95%; a polyurethane layer laminated to the surface of the polyolefin layer facing away from the paper substrate.

The leather-filled paper provided by the invention takes polyolefin as a base material. Because the polyolefin has relatively low melting point and flexibility, good embossing is facilitated by surface texturing. Further, polyolefin has a low amount of odor volatile matter and can reduce or eliminate the need for an additive that easily generates odor, such as a plasticizer, and therefore, it is also advantageous in that the coated paper has a low odor property. The crosslinked polyolefin also provides the leatherette paper with good temperature resistance and wear resistance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a leatherette paper according to an embodiment of the invention.

Fig. 2 is a schematic structural diagram of a leatherette paper according to another embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present invention more clear, the present invention is described in detail with reference to specific embodiments below. It should be understood that the embodiments described in this specification are only for the purpose of explaining the present invention and are not intended to limit the present invention.

For the sake of brevity, only some numerical ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to form ranges not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and similarly any upper limit may be combined with any other upper limit to form a range not explicitly recited. Also, although not explicitly recited, each point or individual value between endpoints of a range is encompassed within the range. Thus, each point or individual value can form a range not explicitly recited as its own lower or upper limit in combination with any other point or individual value or in combination with other lower or upper limits.

In the description herein, it is to be noted that, unless otherwise specified, "above" and "below" are inclusive, and "one or more" of "plural" means two or more.

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The following description more particularly exemplifies illustrative embodiments. At various points throughout this application, guidance is provided through a list of embodiments that can be used in various combinations. In various embodiments, the lists are provided as representative groups and should not be construed as exhaustive.

The invention provides a leather-filled paper which comprises a paper base, a polyolefin layer and a polyurethane layer. The polyolefin layer is laminated on the surface of the paper base, the ingredients of the polyolefin layer comprise 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight, and the crosslinking degree of the polyolefin layer is 1-95%. The polyurethane layer is laminated to the surface of the polyolefin layer facing away from the paper substrate.

In the leathered paper of the present invention, the paper substrate may employ a base for leathered paper known in the art. The paper substrate generally has suitable strength and toughness, which can be selected by one skilled in the art according to the actual needs.

In some embodiments, the grammage of the paper substrate is 40g/m²～300g/m². Further, the grammage of the paper substrate may be 40g/m²～150g/m²，80g/m²～200g/m²Or 80g/m²～130g/m². The gram weight of the paper base is in a proper range, so that the paper base not only has good toughness, tearing resistance and scratch resistance, but also has proper flexibility, and the paper base is convenient to be completely dyed so as to obtain the paper base with saturated and bright color and difficult fading. Further, the grammage of the paper base is in a proper range, and the paper base is easy to be arrangedAnd sizing to improve the adhesion and bonding between the polyolefin layer and the paper base.

The thickness of the paper substrate can be selected according to the requirements of the actual application. In some embodiments, the thickness of the paper substrate is 0.05mm to 0.40mm, 0.10mm to 0.25mm, or 0.15mm to 0.25mm, etc.

The leather-filled paper provided by the invention takes polyolefin as a base material. The polyolefin material is relatively low in price, and has relatively low melting point (the melting point range is 30-180 ℃ or 30-160 ℃) and flexibility (the Shore hardness A is 20-98) at the same time, so that a high simulation effect with soft hand feeling and clear lines can be conveniently formed by means of surface hot pressing or cold pressing treatment and the like. The surface of the leather-filled paper can form any required lines, such as flower stripes, animal skin lines and the like, by taking polyolefin as a base material, and particularly forms an ultra-matte effect which is difficult to realize by PU. And the amount of odor volatile matters generated by polyolefin is very small, compared with solvent type PU leather-filled paper and PVC leather-filled paper added with plasticizer, the leather-filled paper produced by the method has lower odor, and the production process of the leather-filled paper has better environmental protection performance, so that the method can meet the occasions with higher odor and environmental protection requirements.

The polyolefin layer is a cross-linked film layer. The crosslinked polyolefin can provide the leather-filled paper with good abrasion resistance. In some embodiments, the polyolefin layer has a degree of crosslinking of 1% to 95%. Further, the degree of crosslinking of the polyolefin layer may be 3% to 90%, 10% to 95%, 15% to 80%, 30% to 75%, 50% to 90%, 40% to 80%, 50% to 75%, or 60% to 80%, etc. The polyolefin layer has proper crosslinking degree, so that the leatherette paper has high wear resistance and good folding resistance, thereby providing the leatherette paper which has wear resistance, strong leather feeling and good random folding property. The crosslinked polyolefin also enables the leatherette paper to obtain good ageing resistance, temperature resistance and solvent resistance.

Examples of polyolefins may be selected from one or more of polyethylene, ethylene and alpha-olefins, polypropylene, copolymers of propylene and alpha-olefins.

Examples of polyethylene may include Low Density Polyethylene (LDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE). The adoption of polyethylene can lead the leatherette paper to obtain higher wear resistance.

Copolymer of ethylene and alpha-olefin the copolymer of ethylene and alpha-olefin is preferably a copolymer of ethylene and at least one kind selected from the group consisting of alpha-olefins having 3 to 20 carbon atoms. Further, the number of carbon atoms of the alpha-olefin is 4 to 10. For example, the α -olefin may be selected from propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like. The use of copolymers of ethylene and alpha-olefins also allows better embossability of the leathered paper. In addition, the softness and resilience of the leatherette paper can be improved.

The use of polypropylene and/or copolymers of propylene and alpha-olefins allows for higher temperature and abrasion resistance of the leathered paper. The copolymer of propylene and alpha-olefin is preferably a copolymer of propylene and at least one selected from alpha-olefins having 4 to 20 carbon atoms. Further, the number of carbon atoms of the alpha-olefin is 5 to 10. For example, the α -olefin may be selected from 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene, and the like.

The polyolefin may be linear or non-linear.

The polyolefin may be present in the polyolefin layer in an amount of 100%. In some embodiments, the polyolefin layer comprises a tackifying resin in addition to the polyolefin. The tackifying resin may enhance the adhesion between the polyolefin layer and the paper base. The amount of the tackifier resin added can be adjusted according to the actual conditions. In some embodiments, less than 50 parts of tackifying resin may be included in the formulation of the polyolefin layer based on 100 parts by weight of polyolefin. In some embodiments, the polyolefin layer may include 2 to 50 parts, 5 to 50 parts, 4 to 30 parts, 5 to 20 parts, 5 to 10 parts, or 8 to 15 parts of a tackifying resin in the formulation based on 100 parts by weight of the polyolefin.

Examples of tackifying resins may include one or more of rosin, rosin derivatives (e.g., resinates, rosin amines, rosin anhydrides, rosin alcohols, etc.), terpene resins (e.g., alpha-terpene resins, beta-terpene resins), terpene phenolic resins, C5-C9 petroleum resins (e.g., C5 petroleum resins, C9 petroleum resins, C5/C9 petroleum resins, etc.), dicyclopentadiene (DCPD) resins.

In some embodiments, the polyolefin layer further comprises a co-crosslinking agent. The co-crosslinking agent improves the degree of crosslinking of the polyolefin layer. The addition amount of the auxiliary crosslinking agent can be adjusted according to actual conditions. In some embodiments, less than 10 parts of a co-crosslinking agent may be included in the formulation of the polyolefin layer, based on 100 parts by weight of the polyolefin. In some embodiments, the formulation of the polyolefin layer may include 0.1 to 10 parts, 0.2 to 8 parts, 0.5 to 6 parts, 1 to 5 parts, 2 to 5 parts, or 1 to 3 parts of a co-crosslinking agent, based on 100 parts by weight of the polyolefin.

Examples of co-crosslinking agents may include diallylamine, diallyl sulfide, N-dimethyl-bisacrylamide, ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, tetramethylolmethane tetraacrylate, and the like.

In some embodiments, the polyolefin layer further comprises a rubber elastomer. The addition of the rubber elastomer to the polyolefin layer can improve the processability and film-forming properties of the polyolefin layer. The rubber elastomer is preferably a rubber elastomer containing a carbon-carbon double bond. The rubber elastomer has double bonds, whereby the radiation crosslinking effect of the polyolefin layer can be improved and the polyolefin layer can be given a suitable degree of crosslinking.

Examples of the rubber elastomer containing carbon-carbon double bonds may include one or more of Natural Rubber (NR), ethylene-propylene-diene monomer (EPDM), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS). In some embodiments, the rubber elastomer comprises Ethylene Propylene Diene Monomer (EPDM). Preferably, the ethylene content of the ethylene-propylene-diene monomer rubber is 55-75% (mass percentage content). The ethylene propylene diene monomer with appropriate ethylene content is adopted, which is beneficial to improving the crosslinking degree and the vulcanization rate of the polyolefin layer. Preferably, the third monomer of the ethylene-propylene-diene monomer comprises Ethylidene Norbornene (ENB). More preferably, the ethylene propylene diene monomer rubber comprises 2.5 to 5.0 mass percent of ENB. The ethylene propylene diene monomer rubber is beneficial to enabling the polyolefin layer to obtain higher crosslinking degree and vulcanization rate. In some embodiments, the ethylene-propylene-diene monomer rubber has a Mooney viscosity (ML (1+4), 125 ℃, ASTM D1646) of 50 to 75. The Mooney viscosity of the ethylene propylene diene monomer is in a proper range, which is beneficial to leading the polyolefin layer to obtain better processing performance and leading the leatherette paper to obtain higher tensile strength.

In some embodiments, less than 100 parts of the rubber elastomer may be included in the formulation of the polyolefin layer based on 100 parts by weight of the polyolefin. In some embodiments, the formulation of the polyolefin layer may include 10 to 100 parts, 10 to 60 parts, 20 to 90 parts, 30 to 80 parts, 40 to 60 parts, 40 to 80 parts, or 50 to 70 parts of the rubber elastomer, based on 100 parts by weight of the polyolefin.

The polyolefin layer may optionally also contain other additives. Other additives are, for example, antioxidants, colorants, fillers, etc. To further improve the mechanical properties of the polyolefin layer, in some embodiments, the polyolefin layer may comprise one or more fillers of calcium carbonate, limestone, white carbon, talc.

In some embodiments, the polyolefin layer comprises a first polyolefin layer. The first polyolefin layer is laminated to a surface of the paper base, and the first polyolefin layer includes a polyolefin and a tackifying resin. The first polyolefin layer is provided to provide a high bond strength between the polyolefin layer and the paper substrate. In some embodiments, the first polyolefin layer may include 5 to 50 parts, 7 to 30 parts, 5 to 20 parts, 5 to 10 parts, or 8 to 15 parts of a tackifying resin in the formulation based on 100 parts by weight of the polyolefin.

In some embodiments, the first polyolefin layer may comprise less than 10 parts of a co-crosslinking agent in the formulation, based on 100 parts by weight of the polyolefin. In some embodiments, the first polyolefin layer may include 0.1 to 10 parts, 0.2 to 8 parts, 0.5 to 6 parts, 1 to 5 parts, 2 to 5 parts, or 1 to 3 parts of a co-crosslinking agent in the formulation based on 100 parts by weight of the polyolefin.

In some embodiments, the first polyolefin layer may comprise less than 100 parts of the rubber elastomer in the formulation based on 100 parts by weight of the polyolefin. In some embodiments, the first polyolefin layer may include 10 to 100 parts, 10 to 60 parts, 20 to 90 parts, 30 to 80 parts, 40 to 60 parts, 40 to 80 parts, or 50 to 70 parts of the rubber elastomer in the formulation based on 100 parts by weight of the polyolefin.

By way of example, the first polyolefin layer comprises 100 parts of polyolefin, 0-100 parts of rubber elastomer, 5-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight. As another example, the formulation of the first polyolefin layer comprises, in parts by weight, 100 parts of polyolefin, 10 to 60 parts of rubber elastomer, 5 to 20 parts of tackifying resin, and 0.5 to 6 parts of co-crosslinking agent.

The polyolefin, tackifying resin, rubber elastomer, and co-crosslinking agent used in the first polyolefin layer can each be as described herein. The first polyolefin layer may optionally also comprise other additives. Other additives are, for example, antioxidants, colorants, fillers, etc.

The degree of crosslinking of the first polyolefin layer may be 1% to 95%. In some embodiments, the first polyolefin layer has a degree of crosslinking of 3% to 90%, 10% to 95%, 15% to 80%, 30% to 75%, 50% to 90%, 40% to 80%, 50% to 75%, or 60% to 80%, etc.

The thickness of the first polyolefin layer may be determined according to actual requirements. In some embodiments, the first polyolefin layer has a thickness of 0.005mm to 3.5mm, 0.01mm to 2mm, 0.01mm to 1mm, 0.01mm to 0.5mm, or 0.02mm to 0.1mm, and the like.

In some embodiments, the polyolefin layer further optionally comprises a second polyolefin layer. The second polyolefin layer is laminated to the surface of the first polyolefin layer facing away from the paper substrate. In some embodiments, the second polyolefin layer can comprise 100% polyolefin.

In some embodiments, less than 10 parts of a co-crosslinking agent may be included in the formulation of the second polyolefin layer based on 100 parts by weight of the polyolefin. In some embodiments, the formulation of the second polyolefin layer may include 0.1 to 10 parts, 0.2 to 8 parts, 0.5 to 6 parts, 1 to 5 parts, 2 to 5 parts, or 1 to 3 parts of a co-crosslinking agent, based on 100 parts by weight of the polyolefin.

In some embodiments, the second polyolefin layer may comprise less than 100 parts of rubber elastomer in the formulation based on 100 parts by weight of polyolefin. In some embodiments, the second polyolefin layer may include 10 to 100 parts, 10 to 60 parts, 20 to 90 parts, 30 to 80 parts, 40 to 60 parts, 40 to 80 parts, or 50 to 70 parts of the rubber elastomer in the formulation based on 100 parts by weight of the polyolefin.

In some embodiments, the second polyolefin layer can include 50 parts or less, 30 parts or less, 20 parts or less, 10 parts or less, 5 parts or less, or 1 part or less of a tackifying resin in the formulation based on 100 parts by weight of polyolefin. In other embodiments, the formulation of the second polyolefin layer does not contain a tackifying resin. The surface anti-pollution performance of the leathery paper can be improved by reducing or not adding the tackifying resin on the surface layer of the polyolefin layer.

By way of example, the formulation of the second polyolefin layer comprises, by weight, 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent. As another example, the formulation of the second polyolefin layer comprises 100 parts by weight of polyolefin, 10-60 parts by weight of rubber elastomer and 0.5-6 parts by weight of co-crosslinking agent.

The polyolefin, tackifying resin, rubber elastomer, and co-crosslinking agent used in the second polyolefin layer can each be as described previously. The second polyolefin layer may also optionally comprise other additives. Other additives are, for example, antioxidants, colorants, fillers, etc.

The degree of crosslinking of the second polyolefin layer may be 1% to 95%. In some embodiments, the second polyolefin layer has a degree of crosslinking of 3% to 90%, 10% to 95%, 15% to 80%, 30% to 75%, 50% to 90%, 40% to 80%, 50% to 75%, or 60% to 80%, etc.

The thickness of the second polyolefin layer may be determined according to actual requirements. In some embodiments, the second polyolefin layer has a thickness of ≦ 3.5 mm. In some embodiments, the second polyolefin layer has a thickness of 0.005mm to 3.5mm, 0.01mm to 2mm, 0.04mm to 1mm, 0.01mm to 0.5mm, or 0.02mm to 0.1mm, and the like.

The polyurethane layer can play a role in protecting the polyolefin layer, further improve the wear resistance of the leather-covered paper, and improve the performances such as temperature resistance, anti-sticking performance and the like.

The polyurethane layer may employ polyurethane known in the art, such as solvent polyurethane, aqueous polyurethane, or solvent-free polyurethane. In some embodiments, the polyurethane layer is a waterborne polyurethane, or a solventless polyurethane. The use of aqueous polyurethane or solvent-free polyurethane can reduce or eliminate the use of organic solvents, thereby further improving the low odor property of the leatherette paper and also making the preparation of the leatherette paper more environmentally friendly. As an example, the polyurethane layer is made of water-based polyurethane. The polyurethane layer may comprise the following ingredients in parts by weight: 100 parts of waterborne polyurethane, 0-50 parts of deionized water, 0-2.5 parts of thickening agent, 0-10 parts or 0.5-10 parts of isocyanate crosslinking agent and 0-1 part of wetting agent. The solid content of the waterborne polyurethane can be selected from 20-40%, 25-35%, or 30-40%. Specific examples of the isocyanate may include polyether (e.g., polyoxyethylene) graft-modified self-emulsifiable polyisocyanate crosslinking agents, emulsion-emulsifiable polyisocyanate crosslinking agents, and the like. Examples of the thickener may include an associative polyurethane type thickener, an acrylate type thickener, and the like. Specific examples of the wetting agent may include acrylate type wetting agents, silicone type wetting agents, and the like.

The polyurethane layer may also contain water color paste. In some embodiments, the polyurethane layer may contain 0 to 20 parts by weight of the aqueous color paste, or 0 to 10 parts by weight of the aqueous color paste. The water-based color paste can enrich the surface color of the leatherette paper.

The polyurethane layer may also contain one or more of filming agent, feeling agent and polishing slurry. The hand feeling agent can improve the surface hand feeling of the leatherette paper. The matting paste can improve the surface blocking resistance of the leathery paper and can control the gloss of the surface.

In some embodiments, the polyurethane layer has a thickness of 0.005 to 2.0mm, 0.01 to 1mm, 0.01 to 0.5mm, 0.01 to 0.1mm, or 0.02 to 0.05mm, and the like. The polyurethane layer has appropriate thickness, is favorable to filling leather paper and gives consideration to higher embossability and wearability simultaneously better.

In some embodiments, the total thickness of the leathered paper is 0.06mm to 6.9mm, 0.1mm to 5mm, 0.1mm to 3mm, 0.16mm to 2.35mm, 0.15mm to 2mm, 0.15mm to 1mm, or 0.15mm to 0.5mm, and the like.

The invention also provides a preparation method of the leather-filled paper. The leatherette paper can be prepared according to the preparation method. One embodiment of the present invention provides a method for preparing a leather-covered paper, which includes a polyolefin layer preparation step, a polyurethane layer preparation step, and a crosslinking step.

In the preparation step of the polyolefin layer, all raw materials of the polyolefin layer can be uniformly mixed and then extruded by an extruder to be cast on the surface of the paper base to form the polyolefin layer. The polyolefin layer preparation step may be performed using equipment known in the art, such as an extruder. The extruder may employ a T-shaped flat die. If the polyolefin layer comprises a first polyolefin layer and a second polyolefin layer, a coextrusion process may be used to coextrude the formulation of the first polyolefin layer and the formulation of the second polyolefin layer and cast into a film.

In some embodiments, the polyolefin layer is pressure bonded to the paper substrate to achieve a secure bond between the polyolefin layer and the paper substrate. The pressure for pressure bonding may be 0.1MPa to 2.5 MPa.

In some embodiments, a heated roll may be used on the paper-based side. The temperature of the hot roll can be 80-200 ℃. By preheating the paper base, the adhesive force between the paper base and the polyolefin layer can be improved.

In the preparation step of the polyurethane layer, the raw materials of the polyurethane layer can be uniformly mixed, coated or printed on the surface of the polyolefin layer, which faces away from the paper base, and dried to obtain the leatherette paper preform. In some embodiments, the temperature of drying may be 60 ℃ to 200 ℃. For example, hot air drying at 60 to 200 ℃ may be performed by using an air-blowing drying oven.

In some embodiments, after drying the polyurethane coating, a curing step is also included. The polyurethane layer can be appropriately crosslinked by aging, and the surface properties of the leathered paper, such as abrasion resistance, can be improved. In some embodiments, the curing step may be performed prior to the crosslinking step. In some embodiments, the curing step may be performed after the crosslinking step. The curing temperature can be 50-100 ℃. The curing time can be 10-24 h, etc. The curing can be carried out in a constant-temperature constant-humidity heat preservation chamber. The humidity of the heat preservation chamber can be 50-80%, etc.

The crosslinking step comprises crosslinking the polyolefin of the polyolefin layer. In some embodiments, the leatherette paper preform may be radiation crosslinked. This gives the polyolefin layer the desired degree of crosslinking, i.e. the polyolefin layer is a radiation crosslinked polyolefin layer. Radiation crosslinking may be performed using alpha rays, beta rays, gamma rays, X rays, or neutron rays. The crosslinking degree is easier to control by adopting radiation crosslinking, and the crosslinking process is more environment-friendly. When radiation crosslinking is performed, the membrane structure body itself is not in physical contact with the radiation generating device, the shape of the membrane structure body is not changed before and after the reaction, but the crosslinking reaction is already performed in the interior of the membrane structure body. As an example, radiation crosslinking may be performed using beta rays (i.e., high energy electron beams). The radiation dose can be selected from 5 KGy-200 KGy, 10 KGy-100 KGy, 20 KGy-80 KGy, or 50 KGy-150 KGy, etc.

In some embodiments, a surface texturing step may also be included prior to the crosslinking step. In the surface texture processing step, the surface texture processing can be carried out on the leather-filled paper preform to form the required texture. And then carrying out a cross-linking step to obtain the leatherette paper with surface grains. Thereby obtaining the leather-filled paper product with the texture and the stereoscopic style. In some embodiments, the surface texturing step may include: heating the leather-covered paper preform to soften and melt the resin of the polyolefin layer; then the lines of the mould are transferred to the surface of the leatherette paper by vacuum forming, hot-roll hot pressing or cold-roll cold pressing. The plastic suction can be carried out by adopting a suction vein machine; the aforementioned hot or cold pressing may be performed using an embossing machine. In the hot roll hot pressing mode, the temperature of the hot roll may be equal to or slightly lower than the melting temperature of the polyolefin layer resin. Further, the surface texture-treated leatherette paper preform can obtain good pattern retention after being subjected to the subsequent crosslinking step.

The preparation method of the leather-filled paper is simple and low in cost. The invention reduces the use of organic solvent or plasticizer, so the production process is environment-friendly.

Fig. 1 is a schematic view of a structure of a leatherette paper as an example. Referring to fig. 1, the leatherette paper includes a paper base 10, a polyolefin layer 20 laminated to a surface of the paper base 10, and a polyurethane layer 30 laminated to a surface of the polyolefin layer 20 facing away from the paper base 10.

Fig. 2 is a schematic view of the structure of a leatherette paper as another example. Referring to fig. 2, the leatherette paper includes a paper base 10, a polyolefin layer 20 laminated to a surface of the paper base 10, and a polyurethane layer 30 laminated to a surface of the polyolefin layer 20 facing away from the paper base 10. The polyolefin layer 20 includes a first polyolefin layer 21 adhered in contact with the paper base 10 and a second polyolefin layer 22 laminated on a surface of the first polyolefin layer 21 and adhered in contact with the polyurethane layer 30.

The leather-filled paper can meet the requirements of different scenes, such as classical, fashionable, soft or high-gloss, and the like, through different matching of lines, handfeel, gloss and color and matching with various functional effects. The leather filling paper is suitable for various high-grade packages such as binding covers of various gift boxes, jewel boxes, wine boxes, tea boxes, books and paintings, notebooks, cases, collections and the like.

Examples

The present disclosure is more particularly described in the following examples that are intended as illustrations only, since various modifications and changes within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are on a weight basis, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the equipment used in the examples is commercially available.

The polyolefins used in the following examples were selected from:

polypropylene: atactic polypropylene, designation LG chemical R3410;

polyethylene: low density polyethylene, LDPE, designation LG chemical FB 3050;

ethylene-butene copolymer: LG chemical LC 875;

ethylene-octene copolymer: brand dow chemical 8411.

The rubber elastomers used in the following examples were selected from: EPDM, designation dow 3745P.

The aqueous polyurethane used in the following examples was selected from:

shanghai Siwa chemical, PUD-1203, 30% solids content;

shanghai Siwa chemical, HG-24, 25% solids content;

shanghai Lanoho chemical, L556, 40% solids content.

The isocyanate crosslinker used in each of the following examples was selected from:

shanghai Lange chemistry, 50H, polyether modified aqueous self-emulsifying polyisocyanate crosslinkers;

shanghai Kosta Kangchi Kagaku chemical 3035 aqueous emulsion type polyisocyanate crosslinking agent.

The thickeners used in the following examples were selected from:

"Hefei an ke chemical engineering", a50, associative polyurethane thickener;

shanghai Lanoho chemical, C2, acrylate-based thickener.

The wetting agents used in the following examples were selected from:

shanghai Tiger Polymer high tech, 288, silicone-type super wetting agent;

guangzhou siloke chemical 364, acrylate type universal wetting agent.

Preparation of leather-covered paper

(1) The raw materials of the polyolefin layer are uniformly mixed and then extruded by an extruder to be cast on the surface of the paper base to form the polyolefin layer. Alternatively, the formulation of the first polyolefin layer and the formulation of the second polyolefin layer are coextruded and cast onto the surface of the paper substrate to form the polyolefin layer. In order to ensure the consistency of data comparison, the following examples and comparative examples adopt the following process conditions: the pressure of the polyolefin layer and the paper base is 0.3MPa, and the temperature of the hot roller used on the paper base side is 150 ℃.

(2) And uniformly mixing all the raw materials of the polyurethane layer, coating the mixture on the surface of the polyolefin layer, which is opposite to the paper base, drying and curing the mixture to form the polyurethane layer, thus obtaining the leatherette paper preform.

(3) Carry out surface texture to filling leather-covered paper preform and handle, include: heating the leather-covered paper preform to soften and melt the resin of the polyolefin layer; and then, the grains of the die are transferred to the surface of the leatherette paper in a hot pressing mode.

(4) And (3) carrying out radiation crosslinking on the leather-filled paper preform by adopting an electron accelerator to obtain the leather-filled paper.

Example 1

The thickness of the paper base is 0.40mm, and the gram weight is 300g/m²。

The first polyolefin layer was formulated as: 100 parts of polypropylene and 5 parts of tackifying resin (Japan Sanjing petroleum resin, brand FTR 8120).

The second polyolefin layer was formulated as: 100 parts of polypropylene.

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 50 parts of deionized water, 2.5 parts of thickening agent (A50), 10 parts of isocyanate crosslinking agent (50H), 1 part of wetting agent (288), 20 parts of waterborne color paste and a proper amount of hand feeling agent.

In the embodiment, the total thickness of the leatherette paper is 6.0 mm; the thickness of the polyurethane layer is 2.0 mm; the thickness of the second polyolefin layer was 3.5mm, the degree of crosslinking was 3.2%; the first polyolefin layer had a thickness of 0.1mm and a degree of crosslinking of 1.0%.

Example 2

The thickness of the paper base is 0.25mm, and the gram weight is 200g/m²。

The first polyolefin layer was formulated as: 100 parts of polyethylene, 100 parts of rubber elastomer, 50 parts of tackifying resin (terpene resin T80) and 10 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The second polyolefin layer was formulated as: 100 parts of polyethylene, 100 parts of rubber elastomer and 10 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 20 parts of deionized water, 2 parts of thickening agent (C2), 10 parts of isocyanate crosslinking agent (50H), 0.5 part of wetting agent (288), 20 parts of waterborne color paste and a proper amount of hand feeling agent.

In the embodiment, the total thickness of the leatherette paper is 4.85 mm; the thickness of the polyurethane layer is 0.1 mm; the thickness of the second polyolefin layer was 1.0mm, and the degree of crosslinking was 95.0%; the first polyolefin layer had a thickness of 3.5mm and a degree of crosslinking of 92.1%.

Example 3

The thickness of the paper base is 0.1mm, and the gram weight is 80g/m²。

The first polyolefin layer was formulated as: 100 parts of ethylene-butylene copolymer, 60 parts of rubber elastomer, 10 parts of tackifying resin (terpene resin T80) and 3 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The second polyolefin layer was formulated as: 100 parts of ethylene-butylene copolymer, 60 parts of rubber elastomer and 3 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 0 part of deionized water, 0 part of thickening agent, 0 part of isocyanate crosslinking agent, 1 part of wetting agent (288), 5 parts of film-forming agent, 20 parts of waterborne color paste and a proper amount of hand feeling agent.

In the embodiment, the total thickness of the leatherette paper is 0.16 mm; the thickness of the polyurethane layer is 0.01 mm; the thickness of the second polyolefin layer was 0.04mm, the degree of crosslinking was 65.4%; the first polyolefin layer had a thickness of 0.01mm and a degree of crosslinking of 62.7%.

Example 4

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

The polyurethane layer comprises the following ingredients: 100 parts of 25% solid content waterborne polyurethane (HG-24), 0 part of deionized water, 0.5 part of thickening agent (A50), 5 parts of isocyanate crosslinking agent (3035), 1 part of wetting agent (364), 20 parts of waterborne color paste and a proper amount of hand feeling agent.

In the embodiment, the total thickness of the leatherette paper is 0.26 mm; the thickness of the polyurethane layer is 0.02 mm; the thickness of the second polyolefin layer was 0.06mm, the degree of crosslinking was 67.3%; the first polyolefin layer had a thickness of 0.02mm and a degree of crosslinking of 61.5%.

Example 5

The thickness of the paper base is 0.05mm, and the gram weight is 40g/m²。

The first polyolefin layer was formulated as: 100 parts of ethylene-butylene copolymer, 60 parts of rubber elastomer, 10 parts of tackifying resin (terpene resin T80) and 1 part of auxiliary crosslinking agent (triallyl isocyanurate).

Without the second polyolefin layer.

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 50 parts of deionized water, 2.5 parts of thickening agent (A50), 10 parts of isocyanate crosslinking agent (50H), 1 part of wetting agent (364), 20 parts of waterborne color paste and a proper amount of hand feeling agent.

In the embodiment, the total thickness of the leatherette paper is 0.06 mm; the thickness of the polyurethane layer is 0.005 mm; the thickness of the second polyolefin layer was 0 mm; the first polyolefin layer had a thickness of 0.005mm and a degree of crosslinking of 20.6%.

Example 6

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

The second polyolefin layer was formulated as: 40 parts of polyethylene, 60 parts of ethylene-octene copolymer, 60 parts of rubber elastomer and 3 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The polyurethane layer comprises the following ingredients: 100 parts of 25% solid content waterborne polyurethane (HG-24), 20 parts of deionized water, 2 parts of a thickening agent (C2), 10 parts of an isocyanate crosslinking agent (50H), 0 part of a wetting agent, 20 parts of a waterborne color paste and a proper amount of a hand feeling agent.

Example 7

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

The first polyolefin layer was formulated as: 40 parts of polyethylene, 60 parts of ethylene-octene copolymer, 60 parts of rubber elastomer, 10 parts of tackifying resin (terpene resin T80) and 3 parts of auxiliary crosslinking agent (triallyl isocyanurate).

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 50 parts of deionized water, 2.5 parts of thickening agent (C2), 1 part of isocyanate crosslinking agent (50H), 1 part of wetting agent (288), 20 parts of waterborne color paste and a proper amount of hand feeling agent.

Comparative example 1

In this comparative example, the leatherette paper was a PU leatherette paper having a structure of a paper base and a polyurethane layer laminated on one surface of the paper base.

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

And (3) preparing a polyurethane layer: 100 parts of waterborne polyurethane (PUD-1203) with solid content of 30%, 50 parts of deionized water, 2.5 parts of thickening agent (A50), 10 parts of isocyanate crosslinking agent (3035), 1 part of wetting agent (288), 20 parts of waterborne color paste and a proper amount of hand feeling agent; the thickness of the polyurethane layer was 0.02 mm. The raw materials of the polyurethane layer are uniformly mixed and then coated on the surface of the paper base, the paper base is dried and then placed in a constant-temperature constant-humidity heat preservation chamber, the humidity is controlled to be 60-70%, the temperature is controlled to be 50-60 ℃, and the paper base is continuously placed for 24 hours, so that the cured and crosslinked polyurethane layer is obtained.

The total thickness of the leatherette paper is 0.18 mm.

Comparative example 2

In this comparative example, the leatherette paper was PVC leatherette paper having a structure of a paper base and a PVC layer laminated on one surface of the paper base. No radiation crosslinking was performed.

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

The PVC layer comprises the following ingredients: 100 parts of PVC resin powder, 50 parts of plasticizer, 1 part of zinc barium stabilizer, 20 parts of calcium carbonate, 5 parts of color paste and a proper amount of foaming agent; the thickness of the PVC layer is 0.10 mm.

The total thickness of the leatherette paper is 0.26 mm.

Comparative example 3

In this comparative example, the leatherette paper is an environment-friendly EVA leatherette paper, and has a structure of a paper base, an EVA layer laminated on one surface of the paper base, and a polyurethane layer laminated on the surface of the EVA layer. The preparation method is similar to that of the polyolefin leatherette paper of the invention.

The paper base has a thickness of 0.16mm and a grammage of 128g/m²。

The EVA layer comprises the following raw materials: 100 parts of EVA and 3 parts of auxiliary crosslinking agent. The EVA layer had a thickness of 0.1mm and a degree of crosslinking of 69.5%.

The polyurethane layer comprises the following ingredients: 100 parts of waterborne polyurethane with 30% solid content, 50 parts of deionized water, 2.5 parts of thickening agent, 10 parts of isocyanate crosslinking agent, 1 part of wetting agent, 20 parts of waterborne color paste and a proper amount of hand feeling agent. The thickness of the polyurethane layer was 0.02 mm.

The total thickness of the leatherette paper is 0.28 mm.

Comparative example 4

The present comparative example differs from example 4 only in that: the radiation crosslinking step (4) is not performed, i.e., neither the first nor the second polyolefin layer is radiation crosslinked.

Second, test part

1. The above examples and comparative examples were tested for the degree of crosslinking of the first and second polyolefin layers with reference to the xylene extraction method of GB/T29848-. The first polyolefin layer and the second polyolefin layer can be separately made into films under the same formulation composition, film thickness and radiation conditions as the leatherette paper to test the degree of crosslinking.

2. Method for testing peel strength between polyolefin layer and paper base of the leathery paper in each of the above examples and comparative examples: cutting a leather-filled paper test sample with the length of 200mm and the width of 30 mm; the polyolefin layer and the paper base are separated (e.g., peeled by hand) to 50mm, and the separated ends are respectively clamped on the clamps of a tensile tester, and peeled at a speed of 200mm/min at a peel angle of 180 degrees, and the peel force is recorded. The peel strength between the polyolefin layer and the paper substrate was then calculated from the peel strength ═ peel force ÷ sample width. The test can be performed with reference to GB/T8949-2008-5.9.

3. The above examples and comparative examples were tested for the odor rating of the leatherette paper according to QB/T5447 and 2019, determination of odor of Artificial leather test method.

4. The above examples and comparative examples were tested for abrasion resistance according to ASTM D1242-. The test used a CS-10 type friction wheel.

5. The method for evaluating the embossability of the leathery paper in each of the above examples and comparative examples was as follows: the embossability is good when the embossable is at 60-100 ℃ under the embossing pressure of 3-4 MPa; the embossability is medium when the embossability is expressed by the embossability at 100-140 ℃; the embossability is general when the embossability is expressed by the embossability at 100-140 ℃; embossability at 160 ℃ or higher indicates that embossability is particularly poor.

TABLE 1 Performance data sheet for each leatherette paper

As can be seen from the data of examples 1-7, the polyolefin leatherette paper of the invention has good adhesiveness, low odor, good embossability and high wear resistance.

Comparative examples 1 to 4 do not satisfy the present invention, and therefore it is difficult to achieve both low odor property and embossability, and comparative examples 1, 2 and 4 have poor abrasion resistance, and comparative example 1 has low peel strength.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto. Those skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope of the present disclosure, and such modifications or substitutions are intended to be included within the scope of the present disclosure. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.

Claims

1. A leatherette paper comprising:

paper base;

the polyolefin layer is laminated on the surface of the paper base, the ingredients of the polyolefin layer comprise 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight, and the crosslinking degree of the polyolefin layer is 1-95%;

a polyurethane layer laminated to a surface of the polyolefin layer facing away from the paper base.

2. The leatherette paper according to claim 1, wherein the polyolefin layer comprises a first polyolefin layer, the first polyolefin layer is laminated on the surface of the paper base, the first polyolefin layer is prepared from 100 parts by weight of polyolefin, 0-100 parts by weight of rubber elastomer, 5-50 parts by weight of tackifying resin and 0-10 parts by weight of auxiliary crosslinking agent, and the crosslinking degree of the first polyolefin layer is 1-95%;

preferably, the formulation of the first polyolefin layer comprises, by weight, 100 parts of polyolefin, 10-60 parts of rubber elastomer, 5-20 parts of tackifying resin, and 0.5-6 parts of auxiliary crosslinking agent, and the crosslinking degree of the first polyolefin layer is 40-80%.

3. The leather-filled paper according to claim 2, wherein the polyolefin layer further comprises a second polyolefin layer, the second polyolefin layer is laminated on the surface of the first polyolefin layer, which is opposite to the paper base, the second polyolefin layer is prepared from 100 parts of polyolefin, 0-100 parts of rubber elastomer, 0-50 parts of tackifying resin and 0-10 parts of auxiliary crosslinking agent in parts by weight, and the crosslinking degree of the second polyolefin layer is 1-95%;

preferably, the formulation of the second polyolefin layer comprises 100 parts by weight of polyolefin, 10-60 parts by weight of rubber elastomer and 0.5-6 parts by weight of auxiliary crosslinking agent, and the crosslinking degree of the second polyolefin layer is 40-80%.

4. The leatherable paper according to any one of claims 1 to 3, wherein the polyolefin layer is a radiation crosslinked polyolefin layer.

5. The leatherable paper according to any one of claims 1-3, wherein the polyolefin is selected from one or more of polyethylene, ethylene and a-olefin, polypropylene, and a copolymer of propylene and a-olefin.

6. The leatherette paper according to any one of claims 1-3, wherein the rubber elastomer comprises a rubber elastomer containing carbon-carbon double bonds, preferably selected from one or more of Natural Rubber (NR), Ethylene Propylene Diene Monomer (EPDM), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS).

7. The leatherette paper according to any one of claims 1-3, wherein the tackifying resin comprises one or more of rosin, rosin derivatives, terpene resins, terpene phenolic resins, C5-C9 petroleum resins, dicyclopentadiene resins.

8. The leatherette paper as claimed in claim 1, wherein the auxiliary cross-linking agent is selected from one or more of diallylamine, diallyl sulfide, N-methylene bisacrylamide, ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, tetrakishydroxymethyl methane tetraacrylate.

9. The leathered paper of claim 1, wherein the polyurethane layer is selected from a solvent-borne polyurethane, a water-borne polyurethane, or a solventless polyurethane.

10. The leathered paper of claim 3, wherein the leathered paper further satisfies at least one of:

the thickness of the paper base is 0.05 mm-0.40 mm;

the gram weight of the paper base is 40g/m²～300g/m²；

The thickness of the first polyolefin layer is 0.005 mm-3.5 mm;

the thickness of the second polyolefin layer is less than or equal to 3.5 mm;

the thickness of the polyurethane layer is 0.005 mm-2.0 mm;

the total thickness of the leatherette paper is 0.06 mm-6.9 mm.