JP7477258B2 - wallpaper - Google Patents

Description

The present invention relates to wallpaper that is used for interior building materials such as floors, walls, and ceilings, and is particularly excellent in terms of design and scratch resistance.

Wallpapers are known to have a resin layer made of polyvinyl chloride resin or olefin resin laminated onto a base material such as paper, textile, or nonwoven fabric, and then a design is applied using printing or embossing. In particular, if the resin layer is thick at the embossing stage, embossing with large undulations is possible, improving the design.

However, simply making the resin layer thicker increases the mass, which can lead to problems with ease of installation and reduced fire resistance.

Therefore, a method has been adopted in which the resin layer contains a foaming agent to increase the foam thickness after heating, in other words, the foaming ability, as disclosed in, for example, Patent Document 1.

JP 2011-74598 A

However, there was an issue that increasing the foaming rate made the surface softer and reduced scratch resistance.

In other words, the objective of the present invention is to provide wallpaper that has high foaming properties, allowing for highly embossed finishes with high relief, while also ensuring excellent scratch resistance.

As a result of intensive investigations into the above-mentioned problems, it has been found that the problems can be solved by providing a substrate, an expandable polyvinyl chloride-based resin layer laminated on the substrate, and a topcoat layer laminated on the expandable polyvinyl chloride-based resin layer, wherein the expandable polyvinyl chloride-based resin layer contains diisononyl phthalate, the polyvinyl chloride-based resin used in the expandable polyvinyl chloride-based resin layer is a polyvinyl chloride-based resin for paste processing having an average degree of polymerization of more than 1200 and not more than 1600 and an average particle size of primary particles of 0.02 to 20.0 μm , and the expandable polyvinyl chloride-based resin layer contains calcium carbonate in an amount of more than 0 part by weight and not more than 20 parts by weight per 100 parts by weight of the polyvinyl chloride-based resin.

Furthermore , it is also preferred that the topcoat layer is a silicone-acrylate type.

The present invention provides wallpaper with excellent design and scratch resistance.

The basic structure of this invention is a wallpaper that has a foamable polyvinyl chloride resin layer and a topcoat layer applied to a substrate. This is explained in detail below.

"Foamable polyvinyl chloride resin layer"
The expandable polyvinyl chloride resin layer is a layer obtained by expanding a layer made of polyvinyl chloride resin.
The polyvinyl chloride resin used in the expandable polyvinyl chloride resin layer has an average degree of polymerization of more than 1200 and not more than 1600. By limiting the average degree of polymerization within this range, it is possible to achieve both high expandability and scratch resistance. If the average degree of polymerization is 1200 or less, scratch resistance is insufficient, and if it exceeds 1600, expandability decreases. The average degree of polymerization can be measured according to "JIS K 6720-2: 1999 Plastics - Vinyl chloride homopolymers and copolymers (PVC) - Part 2: Preparation of test pieces and determination of various properties".

The polyvinyl chloride resin used in the foamable polyvinyl chloride resin layer may contain vinyl chloride as the main component, but may also contain copolymer components other than vinyl chloride. Specific examples include polyvinyl chloride, ethylene-vinyl chloride copolymer, propylene-vinyl chloride copolymer, vinyl chloride-acrylic resin copolymer, vinyl chloride-urethane copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer, etc. In addition, polyvinyl chloride resins for paste processing and suspension polyvinyl chloride resins can be used as the vinyl chloride resin. Furthermore, these polyvinyl chloride resins may be used alone or in combination of two or more. In particular, the use of polyvinyl chloride resins for paste processing is preferable because it enables paste coating, enables a variety of foamed products by blending a large amount of various compounding agents with inexpensive equipment, and is suitable for small-scale production of a wide variety of products.

Polyvinyl chloride resin for paste processing is a fine polymer particle obtained mainly by emulsion polymerization or microsuspension polymerization, with the average primary particle diameter being, for example, 0.02 to 20.0 μm, and is generally characterized by becoming paste-like when a plasticizer is added. Suspension polyvinyl chloride resin is a porous, amorphous vinyl chloride resin obtained mainly by suspension polymerization, with the average primary particle diameter being, for example, 50 to 200 μm. This porous shape allows it to absorb liquids such as plasticizers, so it does not become paste-like, and is mainly used in extrusion processing and calendar processing.

Diisononyl phthalate (DINP) is used as a plasticizer for the foamable polyvinyl chloride resin layer. Diisononyl phthalate may also be used in combination with other plasticizers. Examples of such plasticizers include phthalic acid plasticizers such as di-2-ethylhexyl phthalate (DOP), diisodecyl phthalate (DIDP), and dioctyl terephthalate (DOTP), polyester plasticizers with a basic structure of polycondensation of dibasic acid and glycol and a molecular weight of 800 to 8,000 obtained by terminating both ends with monobasic acid or monohydric alcohol, and adipic acid esters such as DOA (di-2-ethylhexyl adipate) and DIDA (diisodecyl adipate). It is possible to use aliphatic dibasic acid ester plasticizers such as dibasic acid ester plasticizers, sebacate ester plasticizers such as DOS (di-2-ethylhexyl sebacate), azelaate ester plasticizers such as DOZ (di-2-ethylhexyl azelate), phosphate ester plasticizers such as tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, tris(isopropylated phenyl) phosphate, tris(dichloropropyl) phosphate, and sulfonate ester plasticizers.

Diisononyl phthalate (DINP) is preferably used because it has superior scratch resistance compared to di-2-ethylhexyl phthalate (DOP). Therefore, it is preferable to use diisononyl phthalate (DINP) alone as a plasticizer, or to use diisononyl phthalate (DINP) as the main plasticizer. Furthermore, it is preferable that the amount of other plasticizers used in combination with diisononyl phthalate (DINP) does not exceed the amount of diisononyl phthalate (DINP) added.

The amount of diisononyl phthalate (DINP) added to the foamable polyvinyl chloride resin layer is preferably 20 to 80 parts by weight per 100 parts by weight of polyvinyl chloride resin. If the amount of diisononyl phthalate (DINP) added exceeds 80 parts by weight, scratch resistance may decrease, and bleeding of diisononyl phthalate (DINP) from the wallpaper surface or blocking of the wallpaper may occur. If the amount is less than 20 parts by weight, the plasticization of the polyvinyl chloride resin may decrease, resulting in a decrease in processability. The amount of diisononyl phthalate (DINP) added is more preferably 30 to 60 parts by weight, and even more preferably 35 to 45 parts by weight.

When diisononyl phthalate (DINP) and other plasticizers are added together, the total amount of plasticizers added, including diisononyl phthalate (DINP) and other plasticizers, is considered to be the total amount added, and the total amount added is preferably 20 to 80 parts by weight per 100 parts by weight of polyvinyl chloride resin. If the total amount of plasticizer added exceeds 80 parts by weight, bleeding of the plasticizer from the wallpaper, blocking of the wallpaper, etc. may occur, and the expandable polyvinyl chloride resin layer may not expand sufficiently. If it is less than 20 parts by weight, the expandable polyvinyl chloride resin layer may become rough and a smooth surface may not be obtained. The amount of plasticizer added is more preferably 30 to 60 parts by weight, and even more preferably 35 to 55 parts by weight.

It is preferable that the foamable polyvinyl chloride resin layer contains substantially no filler. The more filler is added, the lower the scratch resistance becomes, so if you want to maximize scratch resistance, it is preferable to not contain any filler.

If cost reduction and improved flame retardancy are required in addition to scratch resistance, a filler can be used in the foamable polyvinyl chloride resin layer. In this case, it is preferable to use more than 0 parts by weight and not more than 20 parts by weight of the filler per 100 parts by weight of polyvinyl chloride resin, and more preferably not more than 15 parts by weight.

The filler is not particularly limited, but examples include calcium carbonate, magnesium carbonate, titanium oxide, magnesium silicate, aluminum hydroxide, ammonium hydroxide, talc, silica, diatomaceous earth, etc., and two or more types may be used in combination.

When a stabilizer is used in the expandable polyvinyl chloride resin layer, it is preferable that it contains a metal halide salt. This improves the thermal stability and further promotes foaming.

Examples of metal halide salts include zinc chloride, iron chloride, magnesium chloride, calcium chloride, barium chloride copper chloride, zinc fluoride, iron fluoride, magnesium fluoride, calcium fluoride, barium fluoride, and copper fluoride, with zinc chloride being particularly preferred. However, zinc chloride promotes dehydrochlorination during processing of polyvinyl chloride, and causes blackening known as zinc burning, so adding large amounts is not recommended. Therefore, it is preferable to add 0.05 to 0.25 wt% of metal halide salt to polyvinyl chloride resin, as this provides sufficient foaming promotion.

The stabilizer may further include a barium-based compound, a calcium-based compound, a barium-based compound, a calcium-based compound, a tin-based compound, a zinc-based compound, a potassium-based compound, etc., with calcium-based compounds being particularly preferred. There are no particular limitations on the amount of calcium-based compound contained, but for example, a content of 0.10 to 0.60 wt% relative to the polyvinyl chloride resin is preferred as this provides sufficient thermal stability and stable foaming properties.

The foaming agent used in the present invention may be any known foaming agent, such as azodicarbonamide, azobisformamide, oxybenzenesulfonylhydrazide, paratoluenesulfonylhydrazide, etc.

Various additives such as colorants, processing aids, antibacterial agents, antifungal agents, flame retardants, defoamers, and viscosity reducers may be added to the foamable polyvinyl chloride resin layer as appropriate, provided that they do not interfere with the solution of the problem.

The basis weight of the expandable polyvinyl chloride resin layer is not particularly limited, but is preferably 130 g/m ² to 200 g/m ² in terms of concealment and workability. If it is less than 130 g/m ² , the concealment may be lacking and workability may be reduced. If it exceeds 200 g/m ² , the fire resistance may be reduced.

Top coat layer
In the present invention, a topcoat layer is applied on the expandable polyvinyl chloride resin layer. The topcoat layer may be made of a silicone compound, a fluorine compound, a urethane compound, an acrylic compound, a vinyl chloride compound, or the like. A copolymer or mixture of two or more of these may also be used, but a silicone-acrylate compound is particularly preferred.

The coating amount of the topcoat layer is not particularly limited, but is preferably 0.5 g/ ^m2 to 6 g/ ^m2 in a dry state. If it is less than 0.5 g/ ^m2 , sufficient scratch resistance may not be obtained. If it exceeds 6 g/ ^m2 , defects such as punctures may occur during embossing.

If necessary, a printed layer or a functional layer may be applied on the expandable polyvinyl chloride resin layer, in which case a topcoat layer is applied on the printed layer or the functional layer.

"Base material"
Examples of the substrates used in the present invention include plain paper (mainly pulp and treated with a known sizing agent), flame retardant paper (mainly pulp and treated with a flame retardant such as guanidine sulfamate or guanidine phosphate), inorganic paper (containing inorganic additives such as magnesium hydroxide or aluminum hydroxide), and fleece paper (made by mixing pulp and synthetic fibers such as polyester). Plain paper is particularly preferred because it improves scratch resistance and workability.

The basis weight of the substrate is not particularly limited, but is preferably 50 g/m ² to 170 g/m ² in terms of hiding power and workability. If it is less than 50 g/m ² , hiding power may be lacking and workability may be reduced. If it exceeds 170 g/m ² , fire resistance may be reduced.

The method for producing the wallpaper of the present invention may be a known method, but it is sufficient to have a step of laminating an expandable polyvinyl chloride resin layer containing a polyvinyl chloride resin on the upper side of the substrate, and a step of providing a topcoat layer on the upper side of the expandable polyvinyl chloride resin layer. For example, a polyvinyl chloride resin composition obtained by blending a plasticizer, a foaming agent, etc. with a polyvinyl chloride resin and kneading it with a blender or the like is laminated on a substrate by a paste coating method or a calendar method to obtain a polyvinyl chloride resin layer. Next, a topcoat layer is laminated on the obtained polyvinyl chloride resin layer using gravure printing, flexographic printing, offset printing, silk screen printing, etc., and the polyvinyl chloride resin layer is foamed with a heater embossing machine or a foaming embossing machine to obtain a foamable polyvinyl chloride resin layer. Furthermore, the surface of the wallpaper can be embossed by mechanical embossing the expandable polyvinyl chloride resin layer.
Furthermore, when a polyvinyl chloride resin layer is laminated on a substrate, paste coating is preferably used, which allows for the use of large amounts of a variety of compounding agents.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

In Example 1, as shown in Table 1, plain paper with a basis weight of 65 g/ ^m2 was used as the substrate, and a paste sol in which a polyvinyl chloride resin with an average degree of polymerization of 1210, diisononyl phthalate, a calcium-zinc chloride stabilizer, and azodicarbonamide were mixed in predetermined amounts was applied with a paste coater to provide a polyvinyl chloride resin layer on the substrate. Next, a silicone-acrylate top coat layer was applied with a dry coating amount of 0.9 g/ ^m2 using a gravure printing machine. After that, the substrate was heated and foamed at 215°C for 40 seconds in a gear oven, and embossed using a mechanical embossing machine.

In Example 2, polyvinyl chloride resin with an average degree of polymerization of 1300 was used, and the amount of diisononyl phthalate was reduced, but the rest of the experiment was similar to Example 1.

Example 3 conforms to Example 1 except that a polyvinyl chloride resin with an average degree of polymerization of 1550 was used.

Example 4 was similar to Example 1 except that the expandable polyvinyl chloride resin layer contained calcium carbonate and the amount of diisononyl phthalate was increased.

Comparative Example 1 was similar to Example 1 except that a polyvinyl chloride resin with an average degree of polymerization of 1050 was used, as shown in Table 2.

Comparative Example 2 conforms to Example 1 except that a polyvinyl chloride resin with an average degree of polymerization of 1700 was used.

Comparative Example 3 was similar to Example 2 except that bis(2-ethylhexyl) phthalate and calcium carbonate were used.

Comparative Example 4 was similar to Example 1 except that a barium-zinc stabilizer that did not contain a metal halide salt was used.

Comparative Example 5 was similar to Example 4 except that a polyvinyl chloride resin with an average degree of polymerization of 1700 was used and the amount of calcium carbonate was increased.

The following evaluations were performed for Examples 1 to 4 and Comparative Examples 1 to 5.

[Foaming evaluation]
When the film was heated and foamed in a Geer oven at 215° C. for 40 seconds before embossing, the film was rated as passed if the foaming ratio (thickness of the foamable polyvinyl chloride resin layer after foaming ÷ thickness of the foamable polyvinyl chloride resin layer before foaming) was 5.1 or more, and was rated as failed if it was less than 5.1.
Each thickness was measured in accordance with 9.3.1 “Measurement of thickness” of JIS P 8118:2014 “Paper and paperboard-Test methods for thickness, density and specific volume” at room temperature without humidity conditioning.

[Scratch resistance]
In accordance with the "Surface-reinforced wallpaper performance standard" set forth by the Wallpaper Industry Association, the surface of a 30 mm x 250 mm test specimen was scratched at a speed of 30 reciprocations per minute using a friction tester type II specified in JIS L 0849 equipped with a friction element with a load of 200 gf. If no relatively large tears in the surface layer were observed, the specimen was rated as passing, and if tears in the surface layer were clearly visible, the specimen was rated as failing.

[Evaluation results]
All of Examples 1 to 4 exhibit good foaming properties and scratch resistance, and are desirable embodiments of the present invention.

In contrast, in Comparative Examples 1 and 3, the average degree of polymerization of the polyvinyl chloride resin was low or diisononyl phthalate was not used, resulting in insufficient scratch resistance. In Comparative Example 2, the average degree of polymerization of the polyvinyl chloride resin was high, resulting in reduced foamability. In Comparative Examples 4 and 5, the foamability and scratch resistance were both unsatisfactory, due to the absence of a stabilizer containing a metal halide salt and the absence of a topcoat layer, or the high average degree of polymerization of the polyvinyl chloride resin and the high calcium carbonate content, respectively.

Claims (2)

A substrate;
A foamable polyvinyl chloride resin layer laminated on the substrate;
and a top coat layer laminated on the expandable polyvinyl chloride resin layer,
the foamable polyvinyl chloride resin layer contains diisononyl phthalate,
The polyvinyl chloride resin used in the expandable polyvinyl chloride resin layer is a polyvinyl chloride resin for paste processing having an average degree of polymerization of more than 1200 and not more than 1600 and an average particle size of primary particles of 0.02 to 20.0 μm ,
The wallpaper comprises in the expandable polyvinyl chloride resin layer more than 0 part by weight and not more than 20 parts by weight of calcium carbonate per 100 parts by weight of the polyvinyl chloride resin. 2. The wallpaper of claim 1 , wherein said topcoat layer is silicone-acrylate based .