JP2023006206A - sheet - Google Patents

Abstract

To provide a sheet that has a calorific value of a substrate reduced as much as possible, has an excellent concealment property, and can be easily and completely peeled from a wall without needing great force when used as wall paper or backing paper for wall paper.SOLUTION: The above-mentioned problem can be solved by a sheet having a substrate containing a pulp and a polyester-based fiber, the substrate provided with a release layer, wherein the mass content ratio between the pulp and the polyester-based fiber is 90:10-60:40, and the release layer involves an alkyl ketene dimer.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a sheet used as a base paper for wallpaper lining paper or a direct-type wallpaper sheet having no decorative layer.

In recent years, there is a demand for wallpaper that can be easily replaced in renovations and remodeling. As a feature of conventional wallpaper, there is a problem that a part of the backing paper remains on the wall side when the wallpaper is peeled off from the wall. In particular, if the wallpaper is replaced frequently, uneven unevenness is formed on the wall side, which affects the finish of the next wallpaper to be pasted, and organic matter accumulates on the wall, which is not good from the viewpoint of fire prevention. . Furthermore, in non-residential properties such as special buildings and large buildings, it is required for fire prevention to suppress the amount of heat generated by the base material itself.

Several inventions have so far been disclosed for wallpaper that can be completely peeled off from walls. Patent Document 1 discloses a nonwoven fabric for wallpaper, which is obtained by impregnating a mixture of polyester fiber and pulp with polyvinyl alcohol or acrylic binder resin. By impregnating the paper with resin, the interlaminar strength of the base material increases, and it is thought that the base material will not break when it is peeled off from the wall. Concealability may be impaired. Also, polyvinyl alcohol and acrylic resin have a higher calorific value than pulp, and have a problem in nonflammability.

US Pat. No. 5,300,000 discloses a wallpaper having a release layer composed of a blend of polyvinyl alcohol solution, dispersant, T-clay and a water resistant/water repellent agent. However, Patent Document 1 and Patent Document 2 do not describe the peel strength, and components such as polyvinyl alcohol have an affinity with the glue (hereinafter sometimes referred to as "wall glue") used for wallpaper construction. is high, and the peel strength tends to be high. Therefore, peeling from the wall is not easy and may require a great deal of force.

Japanese Patent No. 6689644 JP-A-2002-363898

An object of the present invention is to provide a sheet suitable for applications such as wallpaper or backing paper for wallpaper, which minimizes the amount of heat generated by the base material, has excellent hiding properties, and can be easily and completely peeled off from walls.

As a result of intensive studies aimed at solving such problems specific to wallpaper or backing paper for wallpaper, the present inventor focused on the compatibility between the release layer and the wall paste, and improved the releasability by using an alkyl ketene dimer. The inventors have found that the above problems can be solved by the above-mentioned methods, and completed the present invention.

That is, the present invention relates to a sheet comprising a substrate containing pulp and polyester fibers and having a release layer, the release layer containing an alkylketene dimer.

The content ratio of pulp to polyester fiber in the base material is preferably 90:10 to 60:40 in mass ratio.

According to the sheet using the present invention, the alkyl ketene dimer has an appropriate affinity with the wall paste, so that the peel strength can be suppressed. Since it has the effect of suppressing penetration into the interior of the wallpaper or backing paper, it can be easily completely peeled off from the wall without requiring a great deal of force. In addition, by suppressing the amount of resin binder, it is possible to make a sheet with excellent hiding properties without lowering the opacity, and furthermore, by suppressing the heat generation as wallpaper or backing paper for wallpaper, it is possible to create a nonflammable sheet. can provide.

In the sheet of the present invention, a base material containing pulp and polyester fibers is provided with a release layer. The base material is mainly composed of pulp and polyester fibers, and may contain other fibers. For example, acrylic, polyolefin, or nylon fibers may be included. The total content of pulp and polyester fibers in the entire substrate is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more.

The pulp is, for example, softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP) or other wood pulp; non-wood pulp such as kenaf, mitsumata, kozo, cotton; modified pulp such as cationized pulp and mercerized pulp; regenerated cellulose fibers such as rayon and cupra; They can be used in combination. In particular, it is preferable that wood pulp accounts for 90% by mass or more of the entire pulp. The beating degree of the pulp is preferably within 300-500 ml. If it is less than 300 ml, the dimensional stability will be insufficient, and if it is more than 500 ml, the strength will be insufficient, causing paper tearing and the like.

The polyester fiber is a fiber whose constituent component is polyester, and examples thereof include polyethylene terephthalate, polypropylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and combinations thereof. Particularly preferred are polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and combinations thereof. The melting point of the polyester fiber is preferably 180°C or higher, more preferably 200°C or higher. If the melting point is low, a portion of the paper will melt during drying, which may cause the sheet to fluff or stain the dryer. The range of selection narrows in terms of imparting sexuality. Further, the fineness of the polyester fiber is preferably 0.3 to 3.3 dtex, more preferably 0.6 to 2.2 dtex. The fiber length is preferably 3-10 mm, more preferably 4-7 mm. If the fineness is too low or the fiber length is too long, poor dispersion will occur and the texture of the paper will deteriorate, making it impossible to obtain the desired strength and dimensional stability.If the fineness is too high or the fiber length is too short, , because the desired dimensional stability cannot be obtained.

The blending ratio of pulp and polyester fiber is preferably in the range of 90:10 to 60:40, more preferably in the range of 80:20 to 70:30. By setting the thickness within the above range, the water elongation in the transverse grain direction of the paper can be suppressed to 1.0% or less. Elongation in water is determined by JAPAN TAPPI No. 27 "Test method for elongation in water of paper and paperboard". When water-based glue is applied during wallpaper construction, the lower the value, the more the curling and elongation of the paper can be suppressed. Therefore, the sheet of the present invention preferably has a water elongation of 1.0% or less, more preferably 0.9% or less, and even more preferably 0.8% or less. On the other hand, if the blending amount of the polyester fiber is too small, dimensional stability cannot be obtained.

In addition, internal additives such as dry paper strength agents, wet paper strength agents, sizing agents, fillers, yield improvers, and other auxiliary agents can be used for fiber raw materials containing pulp and polyester fibers. Examples thereof include dry paper strength agents such as polyacrylamide and starch, wet paper strength agents such as polyamide/epichlorohydrin-based resins and polyvinylamine-based resins, and sizing agents such as alkylketene dimers. Known fillers such as calcium carbonate, clay, silica, kaolin, and aluminum hydroxide can be used, and titanium dioxide, which is effective in improving opacity, is particularly preferred.

The method for producing the base material of the present invention is not particularly limited, and known paper machines such as a fourdrinier paper machine, a cylinder paper machine, and a twin wire paper machine can be used.

The present invention has solved the problem by focusing on the compatibility between the release layer and the wall glue, which was not conventionally available. As a result of examining various resins and sizing agents for the affinity between methylcellulose-based glue, which is commonly used as wall glue, and the release layer, we found that although the principle is not clear, the release layer mainly made of alkyl ketene dimer is low cost. In the present invention, it has become clear for the first time that the most effective peelability is exhibited at . As a method for applying the release layer to the base material, it is preferable to apply it by a size press or an on-machine coater such as a gate roll from the viewpoint of production efficiency, but an impregnation device, a blade coater, a rod coater, or an air knife coater is preferable. An off-machine coater such as a curtain coater may also be used. The release layer is preferably coated so that the solid content is 0.5 to 6% by mass, more preferably 1 to 5% by mass, and more preferably 1 to 4% by mass, based on the total mass of the substrate. preferable. If it is less than 0.5% by mass, the peelability from the wall is insufficient, so the peel strength is high and peeling becomes difficult, or the substrate is destroyed. If the content is 6% by mass or more, the effect is meaningless, and the amount of heat generated when used as wallpaper or backing paper for wallpaper increases, and the cost also increases. In addition, a resin such as a binder and various auxiliary agents may be added to the release layer to improve the strength to the extent that the concealability and release performance are not impaired. The ratio by mass of the alkylketene dimer in the entire release layer is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more.

Thus, the sheet of the present invention contains an alkylketene dimer as a release layer. Alkyl ketene dimers are represented by the following general formula (1).

（式中、Ｒ１及びＲ２は、それぞれ炭素数８～３０程度のアルキル基又はアルケニル基を表し、同一であっても、異なっていても良い。）

(In the formula, R1 and R2 each represent an alkyl group or alkenyl group having about 8 to 30 carbon atoms and may be the same or different.)

Examples of the alkyl group include octyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group and eicosyl group.

Examples of the alkenyl group include octenyl group, decenyl group, dodecenyl group, tetradecenyl group, hexadecenyl group, octadecenyl group and eicosenyl group.

The amount of the alkyl ketene dimer contained in the substrate is preferably 0.5 to 6% by mass, more preferably 1 to 5% by mass, even more preferably 1 to 4% by mass, based on the entire substrate.

The release layer of the present invention is provided on at least one surface of the base material, and it is preferable that the release layer is provided on the side in contact with the wall surface. The release layer does not need to form a complete "layer", and at least a portion of the contact surface with the surface of the substrate may be blended. For example, part of the release layer may be contained inside the substrate, and the interface between part of the release layer and the substrate may not be clear. However, it is preferable that the amount of part of the release layer contained inside the base material is small, in other words, it is preferable that the amount of part of the release layer existing on the surface of the base material is large. The release layer may be provided on both sides of the substrate. Further, the base material and the release layer do not have to be in contact with each other, and another layer may be provided between them.

The basis weight of the sheet of the present invention is not particularly limited, and may be appropriately determined depending on the application. For example, when used as wallpaper, the basis weight is preferably 120 g/m ² or more and 180 g/m ² or less, more preferably 130 g/m ² or more and 170 g/m ² or less, and 140 g/m ² or more. It is more preferably 160 g/m ² or less. When used as base paper for lining paper for wallpaper, it is preferably 50 g/m ² or more and 100 g/m ² or less, more preferably 60 g/m ² or more and 90 g/m ² or less, and 70 g/m 2 or more. It is more preferably ² or more and 85 g/m ² or less.

When the sheet of the present invention is used as wallpaper, the opacity according to JIS P8138 is preferably 92% or more, more preferably 93% or more, and more preferably 94% or more, in order to provide concealment properties. It is more preferable to have When used as a base paper for wallpaper backing paper, the opacity of the wallpaper backing paper is preferably 88% or more, more preferably 89% or more, more preferably 90% or more. preferable.

When the sheet of the present invention is attached to a wall as wallpaper or backing paper for wallpaper, the peel strength is preferably 1.0 to 5.0 N/3 cm in the evaluation method described later. It is more preferably 2 to 4.0 N/3 cm, more preferably 1.5 to 3.5 N/3 cm.

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

[Example 1]
As pulp, 30 parts by mass of NBKP (beating degree c.s.f. 400 ml) and 70 parts by weight LBKP (beating degree c.s.f. 400 ml) were mixed to prepare a pulp slurry. A fiber raw material was prepared by mixing 100 parts by mass of the pulp with 25 parts by mass of polyester fiber (manufactured by Teijin Limited, product name "TT04N", 1.7 dtex x 5 mm) in terms of solid content. In addition, for the fiber raw material, 5 parts by mass of titanium dioxide (manufactured by Tayca, product name "JA-1") per 100 parts by mass of solid content of pulp, alkylketene dimer-based sizing agent (Arakawa Chemical Industries, Ltd.) (manufactured by Nihon Shokuhin Kako Co., Ltd., product name “TS Starch L1”) 0.1 parts by mass, polyamide/epichlorohydrin resin (manufactured by Seiko PMC) , product name "WS4024") and 0.1 part by mass of polyvinylamine (manufactured by Seiko PMC, product name "Cathiofast VSH") were added to prepare a papermaking raw material. Next, when the papermaking raw material is used to make a base material with a Fourdrinier paper machine, a size press coater is used to coat an alkylketene dimer (manufactured by Seiko PMC Co., Ltd., product name "Surface sizing agent SE2380") as a base material. Coating and drying were carried out so that the content was 3 mass % of the whole, and a sheet with a basis weight of 150 g/m ² was obtained.

[Example 2]
A sheet was obtained in the same manner as in Example 1, except that the amount of alkyl ketene dimer applied using a size press coater was changed to 5% by mass of the entire substrate.

[Example 3]
A sheet was obtained in the same manner as in Example 1, except that no sizing agent was added internally.

[Example 4]
A sheet was obtained in the same manner as in Example 1, except that the alkylketene dimer in the internal sizing agent was changed to a styrene-acrylic type (manufactured by Toho Chemical Industry Co., Ltd., product name "NS-18S").

[Example 5]
A sheet was obtained in the same manner as in Example 1, except that the basis weight was changed from 150 g/m ² to 65 g/m ² . The sheet of Example 5 was used as a coating base paper for wallpaper lining paper, and titanium dioxide (manufactured by Co., Ltd., product name "A-220") and a second Aragonite columnar calcium carbonate (manufactured by Okutama Kogyo Co., Ltd., product name “TP123-CS”) is mixed at a ratio of 70:30 as a pigment, and phosphate esterified starch (manufactured by Nihon Shokuhin Kako Co., Ltd., product name “MS4600”) is used as a binder. 5% by mass and 15% by mass of an acrylic emulsion (manufactured by Mitsui Chemicals, Inc., product name “Bonlon S-415”) were added and diluted with water to a solid content concentration of 55%. Next, this paint was applied to the base paper for coating by an air knife coater so that the solid content was 10 g/m ² and dried to obtain a backing paper for wallpaper having a basis weight of 75 g/m ² .

[Comparative Example 1]
A sheet was obtained in the same manner as in Example 1, except that the alkyl ketene dimer in the size press coater was changed to an olefin polymer (manufactured by Seiko PMC, product name "Surface sizing agent SS2550").

[Comparative Example 2]
A sheet was obtained in the same manner as in Example 1, except that the alkyl ketene dimer in the size press coater was changed to a styrene acrylate polymer (manufactured by Seiko PMC, product name "Surface sizing agent SE2012").

[Comparative Example 3]
A sheet was obtained in the same manner as in Example 1, except that the alkyl ketene dimer in the size press coater was changed to an acrylic polymer (manufactured by Seiko PMC, product name "Paper processing coating agent XP8813"). .

[Comparative Example 4]
A sheet was obtained in the same manner as in Example 5, except that the alkyl ketene dimer in the size press coater was changed to an acrylic polymer (manufactured by Seiko PMC, product name "Paper processing coating agent XP8813"). . Then, this sheet was used as a base paper for coating the lining paper for wallpaper, and in the same manner as in Example 5, a lining paper for wallpaper was obtained.

〔Evaluation method〕
The sheets obtained in Examples and Comparative Examples were evaluated according to the following.
Opacity Opacity was measured according to JIS P8138, and 92% or more of wallpaper was considered acceptable, and 90% or more of backing paper for wallpaper was considered acceptable. Example 5 and Comparative Example 4 measured wallpaper backing paper.
• Peeling strength About 150 g/m ² of a 5% dilution of methylcellulose wall paste (manufactured by Methylan Co., Ltd., product name "AG Special") is applied to a sheet cut into a 3 cm width, and the sheet is attached to a gypsum board. After drying for 48 hours at a room temperature of 23°C and a humidity of 50%, a peel strength test of 300 mm/sec is performed at 90°. Passed.

When the sheets of Examples 1 to 4 were used as direct-type wallpaper, good opacity and peel strength could be obtained. Also, when the sheet of Example 5 was used as backing paper for wallpaper, it was found to have good opacity and peel strength. On the other hand, the sheets of Comparative Examples 1 to 4 had high peel strength due to the influence of the release agent, and the substrate of Comparative Example 1 was destroyed.

As described above, the sheet of the present invention can be expected to provide a beautiful finish even when it needs to be replaced frequently, and it is possible to realize a sheet that satisfies the necessary concealment properties when used as wallpaper or backing paper for wallpaper. .

Claims (2)

A sheet comprising a substrate comprising pulp and polyester fibers and having a release layer, the release layer comprising an alkylketene dimer. 2. The sheet according to claim 1, wherein the content ratio of pulp and polyester fiber is 90:10 to 60:40 by weight.