JP4292928B2 - Method for producing polyolefin decorative sheet - Google Patents

Description

  The present invention relates to a method for producing a decorative sheet that is used as a decorative board by being bonded to a surface of a wood-based board, an inorganic board, a metal plate or the like with an adhesive.

  Makeup used as a veneer by pasting together with adhesives on the surface of wooden boards, inorganic boards, metal plates, etc., which have been used mainly for interior decoration of buildings, joinery, furniture, etc. The sheet has good printability, the degree of hardness and softness can be adjusted by adding a plasticizer, the hardness can be selected according to the application, good embossability, strong interlaminar adhesion strength, and machinability A polyvinyl chloride decorative sheet obtained by printing a wood grain pattern, an abstract pattern or the like on a polyvinyl chloride sheet, which has advantages such as good, etc., has been widely used.

  However, the above-mentioned polyvinyl chloride-based decorative sheet may generate harmful gas when burned. Due to human influences during the combustion process of waste and concerns about environmental conservation, the polyvinyl chloride-based decorative sheet Instead of users, the development of decorative sheets using materials that do not generate toxic gas when burned has been strongly demanded by users.

  Therefore, in recent years, non-vinyl chloride decorative sheets made of polyethylene, polypropylene, polyethylene terephthalate, ethylene-vinyl alcohol, polyester, acrylic, etc., and copolymer resins and paper, which are made of a single layer or a laminate of a plurality of sheets, have become polychlorinated. It has come to be used as an alternative to vinyl decorative sheets. Among them, in particular, a number of polyolefin decorative sheets using polypropylene and polyethylene that have the appropriate flexibility, wear resistance, heat resistance, chemical resistance, etc. required for decorative sheets and that are provided at low cost are proposed. Has been.

  As a method for producing this polyolefin decorative sheet, a method in which a transparent thermoplastic resin layer is laminated on the pattern layer side of a base sheet having a printed pattern layer by an extruder is already known (patent) Reference 1).

  Furthermore, after laminating a transparent thermoplastic resin with an extruder, it is a known technique to subject the surface of the thermoplastic resin to corona treatment and coat polyurethane resin or the like as a surface protective layer.

  However, when trying to manufacture in-line from the lamination of the transparent polyolefin resin layer to the coating of the surface protective layer by an extruder, the crystallization progresses instantaneously, and if the resin that stabilizes is not selected, it will be transparent. Since the surface protective layer is coated before the crystallinity of the polyolefin resin is stabilized, the transparent polyolefin resin layer and the surface protective layer are laminated due to the progress of crystallization of the transparent polyolefin resin after the surface protective layer coating. Stress is applied to the interface, and the adhesiveness of the surface protective layer is lowered due to aging due to ultraviolet rays, temperature, humidity, and the like.

Japanese Patent No. 0630159 is Patent Document 1.

Japanese Patent Laid-Open No. 2003-39613 is Patent Document 2.

  The present invention has been made in view of the drawbacks of the related art, and the transparent polyolefin resin of the produced decorative sheet is used in-line from the extrusion lamination of the transparent polyolefin resin layer of the decorative sheet to the coating of the surface protective layer. It is an object of the present invention to provide a method for producing a polyolefin decorative sheet that prevents deterioration of adhesiveness between a layer and a surface protective layer over time and has little change in physical properties over time.

In order to solve the above problems, first, in the invention of claim 1 of the present invention, a transparent polyolefin resin layer is laminated by extrusion lamination on the outermost layer on the pattern layer side of the polyolefin-based substrate sheet having a pattern layer, and this In the method for producing a polyolefin decorative sheet, in which a surface protective layer is coated in-line after extrusion lamination on the outermost layer portion on the transparent polyolefin layer side of the laminate laminated in the order of the base sheet layer, the pattern layer, and the transparent polyolefin layer, A method for producing a polyolefin decorative sheet is characterized in that the transparent polyolefin resin is heated at 40 ° C. to 60 ° C. between the extrusion lamination portion of the transparent polyolefin layer and the coating portion of the surface protective layer.

  In the invention according to claim 2 of the present invention, the method for producing a polyolefin decorative sheet according to claim 1 is characterized in that the transparent polyolefin layer is subjected to an embossing treatment of unevenness.

  The invention according to claim 3 of the present invention provides a method for producing a polyolefin decorative sheet, characterized in that the embossing treatment according to claim 2 is performed simultaneously with extrusion lamination of a transparent polyolefin resin layer.

  In the invention of claim 4 of the present invention, during the extrusion lamination of the transparent polyolefin resin layer, the maleic acid-modified polyolefin-based adhesive is co-extruded between the transparent polyolefin resin layer and the pattern layer with the transparent polyolefin resin layer. The method for producing a polyolefin decorative sheet according to any one of claims 1 to 3, wherein a functional resin layer is applied.

  The invention according to claim 5 of the present invention is characterized in that, at the time of extrusion lamination of the transparent polyolefin resin layer, an anchor coat layer is applied in advance to the outermost layer on the side opposite to the substrate sheet surface of the pattern layer. A method for producing a polyolefin decorative sheet according to any one of claims 1 to 4.

  By producing a decorative sheet using the production method of the present invention, it is possible to produce a polyolefin decorative sheet having excellent durability and little secular change.

  Furthermore, in this invention, since no vinyl chloride resin is used, there exists an effect which can provide the decorative sheet without a worry of an environmental problem.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an example of a manufacturing process diagram of a decorative sheet according to the present invention. The present invention relates to a pattern layer side of a polyolefin-based substrate sheet (2) having a pattern layer formed by printing a transparent polyolefin resin (1) extruded from an extruder through a T-shaped die (4) in a wide shape. After being extruded and laminated and cooled by a cooling roll (5), it is annealed by a heater zone (6). After the annealing, the surface protective layer is subjected to gravure coating in the gravure coating section (6) after applying the corona treatment machine (7).

  The reason for the annealing treatment by the heater zone is that the annealing treatment accelerates the crystallization speed of the extruded transparent polyolefin resin, and the crystallization sufficiently proceeds until the surface protective layer is coated. It is to make it a state. When the surface protective layer is coated with insufficient crystallization, the load on the interface between the surface protective layer and the transparent polyolefin resin layer due to the progress of crystallization of the transparent polyolefin resin after the surface protective layer is applied. Is in a large state. The decorative board that is pasted to the surface of the base material such as wood or inorganic in that state is relatively less deteriorated in the adhesion of the surface protective layer in the weathering acceleration test using aging and sunshine weather meter. It happens early and the useful life of the decorative board itself is reduced.

  On the other hand, in the case where the annealing treatment is performed after the extrusion lamination, the crystallization of the transparent polyolefin resin proceeds sufficiently, and the coating of the surface protective layer is performed with the transparent polyolefin resin stabilized. The load applied to the interface between the surface protective layer and the transparent polyolefin resin layer is smaller than that of a decorative sheet on which the surface protective layer is coated without annealing. As a result, in the weathering acceleration test using aging or sunshine weather meter when pasted on the surface of a wood or inorganic base material, the adhesiveness of the surface protective layer is reduced and the accompanying decorative plate Its useful life is longer than that of unannealed products.

  As an annealing condition, it is desirable to perform aging at a relatively low temperature of about 40 ° C. to 50 ° C. for a long time. However, in-line annealing often has equipment restrictions such as the length of the annealing zone, and therefore it is necessary to set optimum conditions in consideration of the amount of heat, line speed, annealing zone length, and the like.

  In order to improve the design of the decorative sheet, as shown in FIG. 2, the transparent polyolefin resin layer is subjected to uneven embossing as necessary. The embossing is generally performed by melting the transparent polyolefin resin layer with a high-temperature embossing plate (3) having a concavo-convex pattern before applying the annealing treatment before or after lamination. However, when the extrusion laminating method is used, as shown in FIG. 3, the cooling roll (3) ′ at the time of extrusion laminating is provided with a concavo-convex pattern so that it also functions as an embossed plate, so It is possible to emboss the transparent polyolefin resin layer. This method has a great advantage in terms of manufacturing cost because lamination and embossing can be performed at a time.

  In order to make the adhesion between the transparent polyolefin resin in the extrusion laminate and the pattern base side of the polyolefin-based substrate sheet having the pattern layer more robust, as shown in FIG. Using a method of spraying ozone with the ozone spraying machine (9) on the laminate interface side or a co-extrusion method using two or more extruders, the polyolefin-based adhesive resin (8) is transformed into a transparent polyolefin resin (1 ) And extrusion lamination so that the polyolefin-based adhesive resin is between the transparent polyolefin resin (1) and the pattern-layer side of the polyolefin-based substrate sheet (2) having the pattern layer. In addition, an anchor coating agent is applied to the surface of the polyolefin-based substrate sheet (2) having a pattern layer on the pattern layer side by a gravure coating method. Or a method of computing, a method of applying either individually or in combination of two or more are preferably used.

As a material used for the polyolefin-based adhesive resin (8), maleic acid-modified polyethylene resin is generally used. However, when these resins are used, the heat resistance, particularly the laminate strength at 90 ° C. or more is remarkably lowered. End up. Therefore, not only has a sufficient laminate strength at room temperature, but also when a decorative sheet is exposed to high temperatures, such as when a solvent-free hot melt is used for the adhesive or when a metal plate is used for the substrate. In order to maintain a sufficient laminate strength, it is preferable to employ a maleic acid-modified polypropylene resin having high heat resistance as the adhesive resin (see Patent Document 2).

  Further, the type of the anchor coating agent used in the present invention is not particularly defined, but it is desirable to use an isocyanate curable polyurethane resin that forms a urethane bond by a reaction between a polyol and an isocyanate. Further, when a polypropylene adhesive resin is used, the laminate strength can be further improved by using a urethane anchor coating agent to which an epoxy resin is added. By adding an epoxy-based resin, the adhesion with rubber components such as ethylene-propylene-rubber and styrene-butadiene-rubber, which are generally used as the second component of polypropylene-based adhesive resins, is improved. This is because it becomes stronger.

  In addition, in order to improve the weather resistance of the decorative sheet and the decorative plate made using this decorative sheet, to reduce the secular change, and to prolong the service life, an ultraviolet absorber and light for the transparent polyolefin layer and the surface protective layer are used. Addition of a stabilizer or the like is an essential condition. As the ultraviolet absorber, as long as it has a desired ultraviolet absorption effect and does not significantly affect the properties other than the weather resistance of the decorative sheet, there are no particular restrictions on its components and addition amount, for example, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5 Benzotriazole ultraviolet rays such as chlorobenzotriazole, 2- (3,5-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-5-t-octylphenyl) -benzotriazole Absorbents, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone and other benzophenone purple External line absorbers, triazine ultraviolet absorbers such as 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, cerium oxide, titanium oxide, etc. It is possible to add one or more of these inorganic ultraviolet absorbers in any combination.

  The light stabilizer is not particularly limited as long as it has a desired ultraviolet absorption effect and does not significantly affect the properties other than the weather resistance of the decorative sheet. For example, dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, poly [{6- (1,1,3,3-tetramethylbutyl) amino- 1,3,5-triazine-2,4diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) ) Imino}], N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] — 6-chloro-1,3,5-triazine, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-Butylmalonate Bis Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) and tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate Light stabilizers, benzoate light stabilizers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, bis- (2,2,6,6-tetra It is possible to use one or a combination of one or more of amino ether type light stabilizers such as methyl-1- (octyloxy) -4-piperidinyl) ester.

In addition, a heat stabilizer, a flame retardant, an antiblocking agent, etc. are added as needed. The heat stabilizer is pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl)]-propionate, 2,4-bis- (n-octylthio) -6- (4- Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl -2,4,6-tris (3,5-t-butyl-4-hydroxybenzyl) benzene, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanur Hindered phenolic antioxidants such as acids, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol) ) And the like, and phosphorous antioxidants typified by tris (2,4-di-t-butylphenyl) phosphite, etc., or a combination of one or more can be used. is there.

  Examples of the flame retardant include inorganic compounds such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, and magnesium carbonate, and phosphate ester flame retardants, but there are no particular limitations on the components. However, if it is a non-vinyl chloride sheet in consideration of the environment, it is necessary to consider the use of a halogen-based flame retardant.

  As the anti-blocking agent, an inorganic anti-blocking agent such as aluminum silicate, silicon oxide, hydrotalcite and calcium carbonate, an organic anti-blocking agent such as fatty acid amide, and the like are optionally added.

  On a random polypropylene sheet having a thickness of 70 μm prepared by a calendar method, a wood grain pattern was applied using a gravure coating method using a two-component curable urethane ink. A two-component curable urethane adhesive (manufactured by Mitsui Takeda Chemical Co., Ltd., main agent: Takelac A520, curing agent: Takenate A80) is applied in a thickness of 5 μm, and further, a phenolic antioxidant. 0.2 part by weight, 0.3 part by weight of a hindered amine light stabilizer, 0.5 part by weight of a benzotriazole-based UV absorber, and 0.2 part by weight of an antiblocking agent were added, respectively. The thickness of the transparent homopolypropylene resin layer is obtained by extruding a transparent homopolypropylene resin having a decane extraction residual amount) of 95% or more and an MFR (melt flow rate) stipulated in JIS K6760 of 4 g / min to 5 g / min. Was laminated so as to be 70 μm.

The laminate sheet was heated with a heater at 60 ° C. for 1 minute, and then a two-component curable urethane-based surface protective agent having a light stabilizer and an ultraviolet absorber added to the outermost surface on the transparent homopolypropylene side was 6 μm / m ² in thickness. The decorative sheet of Example 1 was obtained.

<Performance comparison>
About the decorative sheet produced by the manufacturing method of Examples 1-5 and Comparative Examples 1-5, the illuminance 6.5 W / m < ² > and the wavelength are 295--5 using the metal weather meter by Daipuru Wintes Co., Ltd. A weathering accelerated test was performed in which light of 780 nm was irradiated in increments of 60 hours from 0 to 420 hours, and the degree of embrittlement of the surface protective layer was confirmed. As a result, the embrittlement phenomenon of the surface protective layer began to appear in the decorative sheets prepared by the manufacturing methods of Examples 1 to 5 after about 300 hours. On the other hand, the decorative sheets prepared in Comparative Examples 1 to 5 began to show signs of embrittlement after the embrittlement tendency passed 180 hours, and in 240 hours, the obvious embrittlement phenomenon of the surface protective layer was confirmed. It was.

  Further, the decorative sheet produced by the production method in Example 2 and Comparative Example 2 has a design property closer to that of real wood than the decorative sheet produced by the production method in Example 1 and Comparative Example 1. It is a decorative sheet with a much better finish.

  In addition, the decorative sheet produced by the manufacturing method in Example 3 and Comparative Example 3 is manufactured to the extent that cooling and embossing can be performed simultaneously compared to the decorative sheet produced by the manufacturing method in Example 2 and Comparative Example 2. Excellent in terms of cost.

  In addition, the decorative sheet produced by the manufacturing method in Example 4 and Comparative Example 4 has less change over time in the laminate strength than the decorative sheet produced by the manufacturing method in Example 1 and Comparative Example 1. Yes. As a result of the accelerated test using the metal weather meter manufactured by Daipla Intes Co., Ltd., the laminate strength after 120 hours of the decorative sheet produced by the production method of Example 1 and Comparative Example 1 is about 320 N / m. On the other hand, the laminate strength of the decorative sheet produced by the manufacturing method of Example 4 and Comparative Example 4 after 120 hours of metal weathering was about 480 N / m.

  The decorative sheet produced by the manufacturing method in Example 5 and Comparative Example 5 also has less change over time in the laminate strength as compared with the decorative sheet produced by the production method in Examples 1 and 4 and Comparative Examples 1 and 4. It is a decorative sheet. As described above, the results of the accelerated test using a metal weather meter manufactured by Daipla Intes Co., Ltd. show that the laminate strength after 120 hours of the decorative sheet produced by the manufacturing method of Example 5 and Comparative Example 5 is about 600 N / m. The results were superior to the decorative sheets produced by the production methods of Examples 1 and 4 and Comparative Examples 1 and 4.

  A decorative sheet of Example 2 was obtained using the same production method as in Example 1 except that the transparent polypropylene layer was subjected to embossing treatment on the transparent polypropylene layer after extrusion lamination of the transparent homopolypropylene.

  A decorative sheet of Example 3 was obtained using the same production method as in Example 1 except that the transparent polypropylene layer was embossed on the transparent polypropylene layer at the same time as the extrusion lamination of the transparent homopolypropylene.

  During extrusion lamination of the transparent homopolypropylene resin layer, without applying urethane adhesive, instead of coextruding with the transparent homopolypropylene resin layer between the transparent homopolypropylene resin layer and the pattern layer, A decorative sheet of Example 4 was obtained using the same production method as in Example 1 except that a random polypropylene resin layer modified with an acid or its anhydride was applied in a thickness of 10 μm.

  A urethane anchor coat (both made by Mitsui Takeda Chemical Co., Ltd., main agent: Takelac A520, curing agent: Takenate A80) was applied to the pattern layer side with a thickness of 1.2 μm between the random polypropylene layer and the pattern layer. Obtained the decorative sheet of Example 5 using the same production method as in Example 4.

[Comparative example]
In Examples 1-5, the decorative sheet of Comparative Examples 1-5 was obtained using the manufacturing method similar to Examples 1-5 except not heating for 1 minute with a 60 degreeC heater.

  The present invention is mainly used for interior decoration of buildings, surface decorations such as joinery and furniture.

It is a conceptual side view which shows an example of the manufacturing process figure of the decorative sheet concerning this invention. It is a partial conceptual sectional view at the time of melting a transparent polyolefin resin layer and giving a concavo-convex pattern by a hot embossing plate having a concavo-convex pattern in the manufacturing process of the decorative sheet according to the present invention. It is a partial conceptual sectional view at the time of making an uneven pattern on a cooling roll at the time of extrusion lamination in the manufacturing process of a decorative sheet according to the present invention to serve as an embossed plate. It is a partial conceptual sectional view at the time of using the method of spraying ozone in the manufacturing process of the decorative sheet concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent polyolefin resin 2 Polyolefin-type base material sheet 3 Embossed plate 3 'Embossed plate which served as the cooling roll at the time of extrusion lamination 4 T type die 5 Cooling roll 6 Heater zone 7 Corona treatment machine 8 Adhesive resin 9 Ozone spraying machine

Claims (5)

A laminate in which a transparent polyolefin resin layer is laminated by extrusion lamination on the outermost layer on the pattern layer side of a polyolefin-based substrate sheet having a pattern layer, and the substrate sheet layer, the pattern layer, and the transparent polyolefin layer are laminated in this order. In the method for producing a polyolefin decorative sheet, in which a surface protective layer is coated in-line after extrusion lamination on the outermost layer portion on the transparent polyolefin layer side,
A method for producing a polyolefin decorative sheet, comprising heating a transparent polyolefin resin at 40 ° C. to 60 ° C. between the extrusion lamination portion of the transparent polyolefin layer and the coating portion of the surface protective layer.   2. The method for producing a polyolefin decorative sheet according to claim 1, wherein the transparent polyolefin layer is embossed with irregularities.   A method for producing a polyolefin decorative sheet, characterized in that the embossing treatment according to claim 2 is performed simultaneously with extrusion lamination of a transparent polyolefin resin layer.   During extrusion lamination of the transparent polyolefin resin layer, a maleic acid-modified polyolefin adhesive resin layer is applied between the transparent polyolefin resin layer and the pattern layer by co-extrusion with the transparent polyolefin resin layer. The manufacturing method of the polyolefin decorative sheet in any one of Claim 1 to 3. 5. The anchor coat layer is preliminarily applied to the outermost layer of the pattern layer opposite to the substrate sheet surface during extrusion lamination of the transparent polyolefin resin layer. 6. Of manufacturing a polyolefin decorative sheet.