JP7322489B2 - Decorative sheet and decorative member - Google Patents

Description

TECHNICAL FIELD The present invention relates to a decorative sheet, and more particularly to a decorative sheet emitting less carbon dioxide gas and a decorative member using the same.

In recent years, from the viewpoint of preventing global warming, there has been a demand for products with low carbon dioxide emissions in all product genres. Regarding the raw materials used to manufacture products, there is also the issue of how much carbon dioxide is emitted to manufacture the raw materials. Since most thermoplastic resins generally used for decorative sheets are made from naphtha, it has been difficult to reduce the amount of carbon dioxide emissions from decorative sheets.

The decorative sheets described in Patent Documents 1 and 2 are decorative sheets using polylactic acid produced using raw materials derived from agricultural products. Polylactic acid does not depend on petroleum and is synthesized using starch produced from agricultural products such as corn, potato, and sweet potato as a raw material, so it is attracting attention as a reproducible material.

On the other hand, in recent years, attention has been focused on polyethylene resins produced from alcohol made from sugar cane residue. Since this polyethylene resin does not use food as a raw material, it is characterized by not only the effect of reducing carbon dioxide gas, but also the contribution to the global environment as a whole.

These polyethylene resins are generally called biomass polyethylene, and they contribute to reducing the carbon footprint of products.

Specifically, it was found that the surface hardness required for decorative sheets could not be obtained, and problems such as poor bending workability occurred.

Japanese Unexamined Patent Application Publication No. 2008-73998 Japanese Patent Application Laid-Open No. 2008-80703

The problem to be solved by the present invention is to propose a decorative sheet having both sufficient surface hardness and workability while using an eco-friendly biomass polyethylene resin, and a decorative member using the same.

As a means for solving the above problems, the invention according to claim 1 provides a colored thermoplastic resin layer having a pattern layer printed on the surface, and a transparent adhesive resin layer on the surface of the colored thermoplastic resin layer. A decorative sheet in which a transparent thermoplastic resin layer having uneven portions and a surface protective layer are laminated in this order, wherein the transparent thermoplastic resin layer is made of biomass polyethylene resin only, and the transparent thermoplastic resin layer has 20 layers. A decorative sheet comprising a resin composition in which a biomass low-density polyethylene resin of 40% to 80% by mass and a biomass high-density polyethylene resin of 40% to 80% by mass are blended.

The decorative sheet according to the present invention uses a resin composition in which a biomass-derived low-density polyethylene resin and a high-density polyethylene resin are blended as the transparent thermoplastic resin layer. and processability were compatible.

Further, the invention according to claim 2 is the decorative sheet according to claim 1, wherein the transparent thermoplastic resin layer is formed with uneven portions.

Further, the invention according to claim 3 is a decorative member obtained by bonding the back side of the decorative sheet according to claim 1 or 2 to an arbitrary substrate via a primer layer and an adhesive layer.

According to a fourth aspect of the present invention, the decorative member is subjected to a bending process, or the decorative sheet is subjected to a lapping process. It is a decorative member.

The decorative sheet according to the present invention uses a biomass-derived polyethylene resin as a transparent thermoplastic resin layer that occupies a considerable portion of the constituent materials of the decorative sheet, thereby reducing the amount of carbon dioxide generated compared to conventional products. I was able to

By using a resin composition in which a biomass-derived low-density polyethylene resin and a high-density polyethylene resin are blended in a specific ratio for the transparent thermoplastic resin layer, the surface hardness and workability required for a decorative sheet can be achieved. I was able to make it compatible.

Since the transparent thermoplastic resin used in the present invention has a high film transparency, the resulting decorative sheet is excellent in design. In addition, this resin has good workability even in extrusion lamination.

FIG. 1 is a cross-sectional explanatory view schematically showing the layer structure in one embodiment of the decorative sheet according to the present invention. FIG. 2 is a cross-sectional explanatory view schematically showing a layer structure in one embodiment of a decorative member in which the decorative sheet shown in FIG. 1 is bonded to a base material.

The decorative sheet according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a cross-sectional explanatory view schematically showing the layer structure in one embodiment of the decorative sheet according to the present invention. The decorative sheet 9 according to the present invention is a transparent thermal adhesive sheet in which the pattern layer 2 is printed on the surface of the colored thermoplastic resin layer 1, and the pattern layer surface is provided with an uneven portion 7 on the surface via a transparent adhesive resin layer 3. A decorative sheet in which a plastic resin layer 4 and a surface protective layer 5 are laminated in this order, and the transparent thermoplastic resin layer 4 is composed of 20% by mass or more and 60% by mass or less biomass low-density polyethylene resin and 40% by mass or more and 80% by mass. % or less biomass high-density polyethylene resin is blended.

For the colored thermoplastic resin layer 1, a thermoplastic resin composition obtained by adding a pigment, an inorganic filler, a stabilizer, etc. to a thermoplastic resin is molded into a sheet. Thermoplastic resins used here include polyolefin resins such as polyethylene resin, polypropylene resin, polybutene resin, polymethylpentene resin, ethylene-vinyl acetate copolymer or saponified products thereof, ethylene-(meth)acrylic acid ( polyolefin copolymer resin such as ester) copolymer, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polyarylate resin, polycarbonate resin, copolymer polyester resin (typically 1,4-cyclohexane Polyester resins such as dimethanol copolymerized polyethylene terephthalate resin (commonly known as PET-G), acrylic resins such as polymethyl methacrylate, 6-nylon, 6,6 nylon, 6,10 nylon, 12 nylon, etc. Polyamide-based resins, styrene-based resins such as polystyrene, AS resin, and ABS resin, cellulose-based resins such as cellulose acetate and nitrocellulose, and chlorine-containing resins such as polylactic acid resin, polyvinyl chloride, and polyvinylidene chloride. , polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer and other fluorine-based resins, or two or three or more copolymers or mixtures selected from these can be used. can.

The pattern layer 2 is formed by various printing methods, and printing methods such as gravure printing, offset printing, flexographic printing, inkjet printing, and screen printing are used. The most common is the gravure rotary printing method, which can efficiently print a continuous pattern.

As for the ink used to form the pattern layer 2, a dedicated ink is used in which a highly light-resistant pigment is dispersed in a binder suitable for each printing method, taking into consideration the durability required for a decorative sheet. do.

The adhesive resin layer 3 is used for adhering the pattern layer 2 and the transparent thermoplastic resin layer 4 when simultaneously extruding and laminating two layers together with the transparent thermoplastic resin layer 4 . This is essential for polyolefin resins that do not have polar groups. As the adhesive resin, a modified polyolefin resin obtained by introducing various polar groups into a polyolefin resin is used. Maleic anhydride-modified polyethylene resins, maleic anhydride-modified polypropylene resins, and the like are common.

As the transparent thermoplastic resin layer 4, a transparent resin obtained by blending biomass-derived low density polyethylene (LDPE) resin and biomass-derived high density polyethylene (HDPE) resin at a specific ratio is used. As for the ratio, LDPE should be 20% by mass or more and 60% by mass or less, and HDPE should be 40% by mass or more and 80% by mass or less.

When a resin containing more than 60% by mass of LDPE is used as the transparent thermoplastic resin layer 4, the bending workability is good, but the surface hardness is insufficient. is sufficient, but there can be problems with bendability.

The transparent thermoplastic resin layer 4 may contain necessary additives such as heat stabilizers, ultraviolet absorbers, light stabilizers, lubricants and crystallization nucleating agents.

The adhesive resin layer 3 and the transparent thermoplastic resin layer 4 can be efficiently formed by co-extrusion of the two layers using a twin-screw extruder to adhere them to the pattern layer surface. At this time, by using an embossing roll as the cooling roll, the uneven portion 7 can be formed at the same time as the bonding. The concave and convex portions 7 formed in this way have good reproducibility of the embossing roll, and as a result, a decorative sheet with a high design property can be obtained.

A surface protective layer 5 is formed on the surface of the transparent thermoplastic resin layer 4 on which the irregularities 7 are formed. The surface protective layer 5 is formed for the purpose of improving the scratch resistance and surface hardness of the surface of the decorative sheet and imparting an appropriate surface gloss. It is formed by thinly applying a resin composition, usually called a hard coat, such as a mold acrylic resin. Among these, ionizing radiation curable coatings such as ultraviolet curable coatings and electron beam curable coatings are preferable because the time required for curing is short and high hardness coating films can be obtained.

Since the decorative sheet 9 is usually used by bonding it to some base material, a primer layer 6 is formed on the back surface of the colored thermoplastic resin layer 1 for the purpose of improving adhesion to the base material. and good. As the primer layer 6, a coating agent having excellent adhesiveness such as acrylic urethane resin to which a filler is added is used to form a rough surface.

FIG. 2 is a cross-sectional explanatory diagram schematically showing the layer structure in one embodiment of the decorative member 10 in which the decorative sheet 9 shown in FIG. As the base material 8, a metal plate, various wood materials, plastic materials, etc. are used according to the application.

The decorative member 10 in which the decorative sheet 9 is adhered to the base material 8 is generally further subjected to some post-processing. The decorative sheet according to the present invention will be described in more detail with reference to examples below.

<Example 1>
A colored polyethylene resin having a thickness of 55 μm was used as the colored thermoplastic resin layer, the surface of which was subjected to a corona discharge treatment, and then a pattern layer was formed by a gravure printing method using a urethane resin-based ink. An adhesive resin layer and a transparent thermoplastic resin layer were co-extruded on the pattern layer surface using a twin-screw extruder and pressed against an embossing roll to form an uneven portion at the same time as lamination. A maleic acid-modified polyethylene resin was used as the adhesive resin layer. As the transparent thermoplastic resin layer, a resin obtained by blending biomass low density polyethylene (LDPE) resin and biomass high density polyethylene (HDPE) resin at a ratio of 50/50 was used.

A surface protective layer made of an acrylic UV-curable resin was formed on the uneven surface of the transparent thermoplastic resin layer, and a primer layer was formed on the back surface of the colored thermoplastic resin layer after corona discharge treatment. The decorative sheet thus obtained was adhered to MDF (medium density wood fiberboard) using an adhesive to form a decorative member.

<Example 2>
A decorative sheet was produced in the same manner as in Example 1, except that the ratio of LDPE and HDPE in the transparent thermoplastic resin layer was changed to 20/80, and a decorative member was produced in the same manner.

<Example 3>
A decorative sheet was produced in the same manner as in Example 1, except that the ratio of LDPE and HDPE in the transparent thermoplastic resin layer was changed to 60/40, and a decorative member was produced in the same manner.

<Comparative Example 1>
A decorative sheet was produced in the same manner as in Example 1, except that only LDPE was used for the transparent thermoplastic resin layer, and a decorative member was produced in the same manner.

<Comparative Example 2>
A decorative sheet was prepared in the same manner as in Example 1, except that only HDPE was used for the transparent thermoplastic resin layer, and a decorative member was prepared in the same manner.

Each decorative member was evaluated for the following evaluation items.
<Surface hardness>
It was evaluated whether it had sufficient scratch resistance as a decorative sheet.
<Extrusion aptitude>
It was evaluated whether there was any trouble in the production line.
<Transparency>
It was evaluated whether or not there was any problem in terms of design when it was made into a decorative sheet.
<Bending suitability>
V-cut processing aptitude was confirmed using a decorative member bonded to MDF.
Table 1 shows the above results.

Comparative Example 1, in which 100% by mass of LDPE is used as the transparent thermoplastic resin layer, lacks surface hardness, while Comparative Example 2, in which 100% by mass of HDPE is used, lacks bending suitability. In Examples 1 to 3, in which the compounding ratio of LDPE and HDPE is in the range of 20% by mass to 60% by mass and 40% by mass to 80% by mass, respectively, well-balanced performance is exhibited. I understand.

Reference Signs List 1 Colored thermoplastic resin layer 2 Design layer 3 Adhesive resin layer 4 Transparent thermoplastic resin layer 5 Surface protective layer 6 Primer layer 7 Unevenness Part 8...Base material 9...Decorative sheet 10...Decorative member 11...Adhesive layer

Claims (4)

A transparent thermoplastic resin layer having uneven portions formed on the surface thereof and a surface protective layer are laminated in this order on the pattern layer surface of a colored thermoplastic resin layer having a pattern layer printed on the surface thereof, with a transparent adhesive resin layer interposed therebetween. The transparent thermoplastic resin layer is made of biomass polyethylene resin only, and the transparent thermoplastic resin layer contains 20% by mass or more and 60% by mass or less of biomass low-density polyethylene resin and 40% by mass or more and 80% by mass. % or less of a biomass high-density polyethylene resin blended therein. 2. The decorative sheet according to claim 1, wherein the transparent thermoplastic resin layer has uneven portions. A decorative member obtained by laminating the back side of the decorative sheet according to claim 1 or 2 to an arbitrary substrate via a primer layer and an adhesive layer. 4. The decorative member according to claim 3, wherein the decorative member is subjected to a bending process, or the decorative sheet is subjected to a lapping process.

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