JP2017137686A - Backing paper for floor material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide backing paper for a floor material in which the surface flatness after the foamed polyvinyl chloride sol is foamed is improved, the printing surface is minute and gives a beautiful impression as for the floor material, the adhesion with the foamed polyvinyl chloride sol layer is superior, the tear strength is raised and a risk of cut paper is eliminated in the foamed polyvinyl chloride sol coating/foaming process, and the anxiety to a manufacturing process is reduced.SOLUTION: Backing paper for a floor material is formed by containing glass fibers, wood pulp and binder fibers. The backing paper for the floor material is characterized as follows: a first surface layer is a layer containing the wood pulp and not containing the glass fibers; a second surface layer is the layer containing the glass fibers, the wood pulp and the binder fibers; the second surface layer contains core sheath type polyester composite fibers as the binder fibers; a content ratio of the core sheath type polyester composite fibers is 1 mass% or more and is less than 10 mass% to all fibers of the second surface layer; and a coating layer is provided in the second surface layer side.SELECTED DRAWING: None

Description

  The present invention relates to a backing paper for flooring.

  A flooring material having a foamed polyvinyl chloride (foamed vinyl chloride sol) layer is coated with a foamed vinyl chloride sol on a flooring backing paper containing glass fiber, gelled and printed by heating, and transparent non-coated on it. After the foamed PVC sol is applied, the whole is heated to foam the foamed PVC sol, thereby forming a foamed PVC sol layer.

  Recently, a high level of flatness of the flooring surface has been demanded. This is because, if the surface is flat, in addition to the appearance, the printing is clear and the printing is preferable for the user.

  In order to obtain a flooring material having high surface flatness, the surface after foamed vinyl sol is applied and foamed after gelation needs to be flat. However, the backing paper for flooring containing glass fiber has a porous structure because it contains glass fiber having a fiber diameter of 5 to 10 μm, and the penetration of the foamed vinyl sol tends to be uneven, and the foamed vinyl sol foams. The foaming state is not uniform and the surface is difficult to be flat. For this reason, attempts have been made to obtain uniform flatness by flattening the floor backing paper containing glass fibers and suppressing the permeation of the foamed PVC sol, thereby obtaining flatness.

  In addition, in order to obtain flatness, the foamed PVC sol is applied to the backing paper for flooring that has been stretched by applying a high tension, so in the coating process, the drying process and the foaming process of the foamed PVC sol It is important that the backing paper for flooring is not cut or torn.

  In order to close the eyes of the backing paper for flooring, a technique for closing the eyes with aggregates of synthetic resin emulsions such as styrene butadiene rubber (SBR) and polyvinyl chloride and polyvinyl alcohol (PVA) fibers has been proposed ( For example, see Patent Document 1). However, synthetic resin emulsions and PVA fibers have not been sufficiently effective to close the eyes.

  A method for covering the surface of a backing paper for flooring containing glass fibers with flat fibers such as wood pulp has also been proposed. By covering the layer containing glass fiber with a layer containing mainly wood pulp, which does not contain glass fiber, the skin irritation on the back side of the backing paper for flooring is reduced and the handling operator is protected. (For example, patent document 2). However, if the amount of wood pulp in the layer containing glass fiber is increased, the glass fiber on the layer side containing glass fiber can be coated and the surface becomes flat. However, wood pulp has low water resistance and heat resistance, and the dimensional stability of flooring backing paper may be reduced by water or heat, so the amount is limited, so the effect is not sufficient It was.

Further, a resin composition containing 1.5 g / m ² or more of latex in a solid content is applied to a layer containing glass fiber by 5 g / m ² or more, and on the side opposite to the side on which the resin composition is applied, A backing paper for flooring having a two-layer structure provided with a layer substantially free of glass fibers has been proposed, but there is little uneven penetration of the foamed PVC sol, and the foamed PVC sol foams uniformly, It is desired that the surface be flat (see, for example, Patent Document 3).

  In addition, a backing paper for flooring having a two-layer structure in which the first layer includes pulp fibers and a fibrous binder and the second layer includes glass fibers, crimped pulp, pulp fibers, and fibrous binders has been proposed. (For example, refer to Patent Document 4). In this backing paper for flooring, cushioning properties and heat insulation properties are enhanced by crimped pulp, and PVA fibers and core-sheath polyester fibers are used as fibrous binders. However, although the tensile strength is increased by the PVA fiber, the tear strength may be decreased, and there may be a problem that paper breakage occurs in the foamed vinyl chloride sol coating / foaming process. In addition, when a large amount of core-sheath polyester fiber is blended, the voids of the backing paper for flooring increase, so that the resin composition may penetrate too much into the backing paper for flooring, and the flatness after coating with foamed PVC sol There were cases where it worsened.

Japanese Patent Publication No.58-4618 Japanese Patent Publication No.57-26232 Japanese Patent No. 3468994 JP 2009-228138 A

  The present invention improves the flatness of the surface after foaming of the foamed vinyl chloride sol, gives a fine and clean impression as the flooring material, and has good adhesion to the foamed vinyl chloride sol layer, tear strength It is an object of the present invention to provide a backing paper for flooring that does not have to worry about paper breakage in the foamed vinyl chloride sol coating / foaming process and is less worried about the manufacturing process.

  The above problems have been solved by the following means.

(1) In a backing paper for flooring comprising glass fiber, wood pulp and binder fiber, the first surface layer is a layer containing wood pulp and not containing glass fiber, and the second surface layer is glass fiber. , A layer containing wood pulp and binder fiber, the second surface layer contains a core-sheath type polyester composite fiber as a binder fiber, and the core-sheath type polyester composite fiber with respect to all the fibers of the second surface layer The flooring paper for flooring is characterized by having a content ratio of 1% by mass or more and less than 10% by mass and having a coating layer on the second surface layer side.

(2) The backing paper for flooring according to the above (1), wherein the second surface layer further contains polyvinyl alcohol fibers as binder fibers.

(3) The backing paper for flooring according to the above (2), wherein the content ratio of the polyvinyl alcohol fiber is 1% by mass or more and less than 10% by mass with respect to all the fibers of the second surface layer.

  According to the present invention, the flatness of the surface after foaming of the foamed PVC is improved, the printed surface as the flooring gives a fine and clean impression, and the adhesiveness with the foamed PVC layer is good, tearing It is possible to provide a backing paper for flooring that has high strength and does not have to worry about paper breakage in the foamed vinyl chloride coating / foaming process and is less worried about the manufacturing process.

  Hereinafter, the backing paper for flooring of the present invention will be described in detail.

  In the present invention, the present inventors have eagerly worked on how to provide a backing paper for flooring whose surface flatness after coating / foaming of foamed PVC is greatly improved. As a result, in the backing paper for flooring comprising glass fiber, wood pulp and binder fiber, the first surface layer is a layer containing wood pulp and not containing glass fiber, and the second surface layer is glass fiber. , A layer containing wood pulp and binder fiber, the second surface layer contains a core-sheath type polyester composite fiber as a binder fiber, and the core-sheath type polyester composite fiber with respect to all the fibers of the second surface layer The surface on which the foamed vinyl chloride sol layer is provided by the backing paper for flooring, characterized in that the content ratio is 1 mass% or more and less than 10 mass% and has a coating layer on the second surface layer side (coating surface) The tear strength of the second surface layer to be increased, firmly fixing the intersection with the flat wood pulp, while suppressing the movement of the wood pulp during coating, while maintaining the flatness peculiar to wood pulp, Smooth coating Since the layer is obtained, it is possible to obtain a high flatness foam salts Bizoru layer. In addition, by containing the core-sheath type polyester composite fiber, the sheath part melted and softened adheres the intersection with the fiber contained in the second surface layer to increase the tensile strength and the tear strength. Thus, it is possible to suppress paper breakage in the foamed vinyl chloride coating / foaming process. Further, when the flooring material is attached to the floor surface or the like, it can be made difficult to tear against twisting or twisting. In addition, the core portion that does not melt can create voids between the fibers contained in the second surface layer, can ensure air passage in the foaming process of the foamed vinyl chloride sol, and can suppress poor foaming.

  The backing paper for flooring of the present invention has a multilayer structure of two or more layers, and has a first surface layer and a second surface layer. The first surface layer is a layer containing wood pulp and not containing glass fibers, and the second surface layer is a layer containing glass fibers, wood pulp and binder fibers. The first surface layer is a layer serving as the back surface of the flooring material and covers the glass fiber of the second surface layer to prevent skin irritation and protect the environment of handling workers and users. The backing paper for flooring of the present invention may have a two-layer structure including only the first surface layer and the second surface layer, or another layer is provided between the first surface layer and the second surface layer. Three or more layers may be used.

  In the present invention, the glass fiber may be any glass fiber as long as it is difficult to break and has a fiber sheet forming ability. As a fiber diameter of glass fiber, Preferably it is 3-20 micrometers, More preferably, it is 5-15 micrometers, More preferably, it is 6-13 micrometers. The fiber length of the glass fiber is preferably 3 to 25 mm, more preferably 5 to 20 mm, and still more preferably 6 to 13 mm. Further, since the concrete to which the flooring is pasted is alkaline, alkali-resistant E glass is preferable.

  In the present invention, the wood pulp is softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), hardwood bleached sulfite pulp (LBSP), groundwood pulp (GP), thermomechanical. Pulp (TMP) or any other kind of pulp may be used, and is not particularly limited. NBKP is preferable from the viewpoint of clogging and strength. The Canadian standard freeness is preferably in the range of 300 to 600 ml (300 ml CSF to 600 ml CSF). The surface can be flattened with wood pulp, which is a flat fiber, and the surface can be made flat.

  Examples of the binder fiber include a composite fiber such as a core-sheath fiber (core-shell type), a parallel fiber (side-by-side type), and a radial split fiber; an unstretched fiber, and the like. More specifically, cores such as a combination of polypropylene (core) and polyethylene (sheath), a combination of polypropylene (core) and ethylene vinyl alcohol (sheath), a combination of high melting point polyester (core) and low melting point polyester (sheath), etc. Examples include unstretched fibers such as sheath fibers and polyester. Moreover, the single fiber (total melt type) comprised only by low melting-point resin, such as polyethylene and a polypropylene, hot water soluble binder fiber like a polyvinyl alcohol type, etc. are mentioned. The cross-sectional shape of the binder fiber is not particularly limited, and may be not only a circular shape but also an irregular cross-sectional shape such as a T shape, a Y shape, or a triangle.

  In the present invention, the second surface layer contains a core-sheath type polyester composite fiber as a binder fiber. In the second surface layer, the presence of the core-sheath polyester fiber between the wood pulps and between the wood pulp and the glass fibers increases the voids, so that the air escape route when foamed PVC sol is foamed is increased. Can be secured, and the surface can be flat. Further, by bonding wood pulps having poor water resistance, strength can be maintained even in a wet state, and tear strength that tends to decrease when wood pulp is contained can be increased.

  The core-sheath type polyester composite fiber is a combination of a high melting point polyester (core) and a low melting point polyester (sheath). The sheath is preferably a copolyester. Copolyester includes a terephthalic acid component and an ethylene glycol component, and an isophthalic acid component, adipic acid component, sebacic acid component, naphthalenedicarboxylic acid component, diethyl glycol component, 1,4-butanediol component and aliphatic Examples thereof include a copolyester containing at least one component selected from the group of lactone components. This copolyester may be amorphous or crystalline. The core is preferably a polyester whose main repeating unit is alkylene terephthalate, and is preferably polyethylene terephthalate having high heat resistance.

  In the present invention, the cross-sectional shape of the core-sheath polyester composite fiber is not particularly limited, but is preferably circular. Further, the ratio of the core part to the sheath part is preferably in the range of core / sheath = 30/70 to 70/30, more preferably 40/60 to 60/40, in terms of volume ratio.

  The fineness of the binder fiber is preferably 0.1 dtex to 5.6 dtex, more preferably 0.6 dtex to 3.3 dtex, and still more preferably 1.1 dtex to 2.2 dtex. If it is less than 0.1 dtex, the density may increase and it may be difficult to secure a void. On the other hand, when it exceeds 5.6 dtex, there are cases where the number of contact points between the fibers becomes too small and it is difficult to maintain the strength. In addition, there is a case where a uniform texture cannot be obtained.

  The fiber length of the binder fiber is preferably 1 to 20 mm, more preferably 2 to 15 mm, and still more preferably 3 to 10 mm. If it is less than 1 mm, it may fall off from the papermaking wire during papermaking, and sufficient strength may not be obtained. On the other hand, if it exceeds 20 mm, it may cause tangles when dispersed in water, and a uniform texture may not be obtained.

  In the second surface layer, the compounding ratio (mass basis) of the glass-sheath: wood pulp: core-sheath polyester composite fiber as the binder fiber is preferably 20-60: 30-70: 1-10, respectively. More preferably, it is 25-55: 35-65: 2-9. When the content ratio of the glass fiber is less than 20% by mass, the shrinkage and elongation due to the temperature difference of the foamed vinyl chloride sol coated product is increased, it becomes difficult to obtain dimensional stability, and there is a gap on the floor surface, Dandruff may occur. Moreover, even if the content rate of glass fiber exceeds 60 mass%, there is no change in dimensional stability and an effect does not change. When the ratio of the wood pulp is less than 30% by mass, the clogging effect is small, the amount of coating liquid penetrating into the second surface layer increases, and a flat coated surface may not be formed. Moreover, the entanglement between the fibers is reduced, and the tear strength may be lowered. On the other hand, when the content ratio of the wood pulp exceeds 70% by mass, the ratio of the glass fibers decreases, and it may be difficult to obtain dimensional stability. When the blending ratio of the core-sheath type polyester composite fiber as the binder fiber is less than 1% by mass, it may be difficult to obtain the tear strength. On the other hand, when the content is 10% by mass or more, voids in the second surface layer can be secured, the tear strength is increased, and the clogging effect may be reduced.

  The second surface layer may contain polyvinyl alcohol (PVA) fiber as the second binder fiber in addition to the core-sheath type polyester composite fiber as the binder fiber. PVA fiber is a fibrous binder containing a hydroxyl group. PVA fiber is a fiber manufactured under appropriate conditions using an appropriate raw material PVA, and maintains a fiber form while hardly dissolving in room temperature water, but is heated in a wet paper state with moisture after paper making. When the wet paper web is pressurized, the PVA fibers straddle between the fibers to become a fibrous binder and re-solidify by subsequent dehydration drying. This makes it possible to obtain a smooth surface with less fuzz than when only the core-sheath type polyester fiber is contained as the binder fiber. When the second surface layer further contains PVA fibers, the content ratio is 1% by mass or more and less than 10% by mass, preferably 2% by mass or more and 8% by mass or less, based on the total fibers of the second surface layer. It is. Even when the blending ratio of the PVA fibers is 10% by mass or more, further improvement in smoothness cannot be expected, and air permeability may be lowered.

  The backing paper for flooring of the present invention has a coating layer on the second surface layer side. Then, a foamed vinyl chloride sol layer is provided on the coating layer to form a flooring. When the glass fiber is exposed on the surface opposite to the side where the coating layer is provided, it is preferable for hygiene because it stimulates the worker in the process of processing the floor material and the work of actually attaching the floor. Absent. Then, the 1st surface layer which does not contain glass fiber in the opposite side to the side in which a coating layer is provided is provided. The first surface layer contains wood pulp, but may contain binder fibers in addition to wood pulp. The content ratio of the binder fiber is preferably 30% by mass or less, more preferably 20% by mass or less, with respect to the total fibers of the first surface layer. When the content ratio of the binder fiber exceeds 30% by mass, the interlaminar strength between the first surface layer and the second surface layer is excessively increased, and it becomes difficult to peel off between the first surface layer and the second surface layer during re-stripping. In some cases, it may be peeled off between the second surface layers, or may be peeled off between the floor surface and the first surface layer, and the floor surface after peeling may not be flat and a new floor material may not be applied cleanly.

The basis weight of the first surface layer is sufficient as long as it covers the glass fibers of the second surface layer, but is preferably 3 to 30 g / m ² . The basis weight of the second surface layer is preferably 40 to 130 g / m ² .

  The backing paper for flooring of the present invention can be produced by drying wet paper sheeted by a wet papermaking method.

  Examples of the papermaking method used for forming a sheet by the wet papermaking method include a long mesh method, a circular mesh method, and an inclined wire method. A paper machine having one papermaking system selected from these papermaking systems may be used, or a combination papermachine having two or more of the same or different papermaking systems selected from these papermaking systems may be used. .

  As a method for producing a multi-layered flooring backing paper, there is a laminating method in which wet papers made by each paper making method are laminated, and a slurry in which fibers are dispersed is cast on a previously formed layer. And a casting method in which other layers are formed and laminated. In the casting method, the previously formed layer may be in a wet paper state or in a dry state. Further, two or more dry layers can be thermally fused to form a multilayer structure.

  As a method for drying wet paper produced by a wet paper machine, a dried sheet is obtained by drying with a Yankee dryer, an air dryer, a cylinder dryer, a suction drum dryer, an infrared dryer or the like. In particular, when the wet paper is dried, it is brought into close contact with a hot roll such as a Yankee dryer and dried by heat and pressure to improve the smoothness of the contacted surface. Hot-pressure drying means that the wet paper is pressed against the heat roll with a touch roll or the like and dried. The surface temperature of the hot roll is preferably 100 to 180 ° C, more preferably 100 to 170 ° C, and still more preferably 110 to 160 ° C. The pressure is preferably 50 to 1000 N / cm, more preferably 100 to 800 N / cm.

  In the present invention, the coating layer can be formed by coating a coating liquid containing a pigment and a binder. As the pigment, it has an affinity with the binder, there is little pigment removal after coating, and it only needs to have an action of retaining the binder on the surface of the second surface layer. Clay, kaolin, calcined kaolin, talc, calcium carbonate, carbon dioxide Titanium or the like can be used. Moreover, in order to give self-extinguishing property, aluminum hydroxide, magnesium hydroxide, etc. can also be used. When the total of the first surface layer and the second surface layer is 100% by mass, the ratio of the pigment to be applied is preferably 3 to 50% by mass, more preferably 5 to 45% by mass, and still more preferably. 7 to 40% by mass. When the pigment application ratio is less than 3% by mass, the flatness improvement effect of the second surface layer may not be obtained. Moreover, when the application ratio of the pigment is more than 50% by mass, the flatness of the second surface layer is not further improved, and the workability may be deteriorated because the weight as a flooring material is increased.

  It is desired that the binder used for the coating layer has high suppression of permeation of the foamed PVC, has good adhesion to the foamed PVC, and has a sealing effect on the backing paper surface for flooring. Examples of the binder include polyvinyl chloride, styrene butadiene, acrylic, vinyl acetate, and styrene acrylic. An aqueous dispersion binder (latex binder) can be preferably used as the binder because of its good adhesion to the foamed vinyl chloride sol. The content ratio of the binder contained in the coating layer is preferably 10 to 40% by mass, more preferably 20 to 35% by mass. When the content ratio of the binder is less than 10% by mass, the pigment may not be sufficiently retained on the second surface layer, and the pigment may fall off. When the content ratio of the binder is more than 40% by mass, the air permeability of the coating layer is deteriorated, and there is a case where it is not possible to secure a passage for air when foaming the foamed vinyl chloride sol.

  The coating method of the coating layer may be selected and used according to the coating amount and the viscosity of the coating liquid by various coating methods such as air knife, blade coating, gravure coating, kiss coater, and offset coating. . The gravure coating method is preferable because it can be applied to porous backing paper for flooring material with a small coating amount and efficiently without the coating layer penetrating into the second surface layer. According to the gravure coating method, the coating amount can be adjusted by adjusting the cell depth and mesh of the gravure roll (engraved roll) in addition to the concentration and viscosity of the coating liquid. Furthermore, by combining with offset coating, the linear pressure during coating can be reduced, so that the coating layer can be adhered to the surface of the second surface layer and effectively clogged.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a present Example. In the examples, all parts and percentages are by mass unless otherwise specified.

<Evaluation>
The following evaluation was performed on the backing paper for flooring materials obtained in Examples and Comparative Examples, and the evaluation results of surface flatness, peel strength, and tear strength are shown in Table 2.
[Surface flatness]
The backing paper for flooring is cut into a width of 25 cm and a length of 30 cm, preheated with a constant temperature hot air dryer at 110 ° C. for 30 seconds, and then placed on the glass plate so that the second surface layer is on top. Foamed vinyl sol for the material (viscosity 5000 to 8000 mPa · s, B-type viscometer) was applied with an applicator bar having a gap of 0.4 mm, and heated for 20 seconds in a constant temperature hot air dryer at 200 ° C. to be gelled. A non-foamed transparent polyvinyl chloride sol was coated on the gelled foamed vinyl sol that had been taken out and cooled with an applicator bar having a gap of 0.6 mm, and then placed on the sample underlay and then placed in a 200 ° C constant temperature hot air dryer for 150 seconds. By heating, the foamed PVC sol was foamed and the non-foamed PVC sol was gelled to prepare a flooring.

  The floor surface of the prepared floor material was visually observed for unevenness on the surface of the vinyl chloride, and the one with the least unevenness was graded 1 and the one with the largest unevenness was graded 1-5. When grade 3 or lower was obtained, it was judged that “flatness was improved”.

[Peel strength]
The adhesion between the backing paper for flooring and the foamed vinyl chloride sol layer was evaluated. The floor material produced above was cut into a width of 50 mm and a length of 200 mm, and a tear was made with a cutter knife between the flooring backing paper and the foamed vinyl chloride sol layer, and then peeled off by 3 cm by hand and observed in a peeled state did.

Of the “◯” peeled off by 3 cm, 2 cm or more peeled off within the foamed vinyl chloride sol layer.
“Δ” 3 cm of the peeled, 2 cm or more peeled in the backing paper for flooring.
Of the “×” 3 cm peeled, 2 cm or more peeled between the foamed vinyl chloride sol layer and the backing paper for flooring.

[Tear strength]
The average value (unit: mN) of the vertical direction (MD) and the horizontal direction (CD) was calculated by JIS P8116 2000 Elmendorf-type tear tester method.

Example 1
Dispersion of glass fibers (9 μm × 6 mm, manufactured by Asahi Fiber) was performed as follows. In the pulper, water and a nonionic surfactant (trade name: Nonion NS-206, manufactured by NOF Corporation, 2% by mass of glass fiber) as an initial dispersant were added and stirred, then glass fiber was added and stirred for 15 minutes. . Thereafter, 4% by mass of glass dispersion (trade name: SN Dispersant 5034, manufactured by San Nopco) was added as a dispersion stabilizer, and then an aqueous solution of polymer polyacrylamide (trade name: Acrypers PNS, manufactured by Mitsubishi Rayon) was added to glass fiber 1. 0 mass% (solid) was added, and the mixture was stored in a state of being stirred with a reciprocating rotary stirrer (manufactured by Shimazaki Seisakusho).

  NBKP (wood pulp, trade name: Chinook, Canadian standard freeness 500 ml CSF) and core-sheath type polyester composite fiber 1 (binder fiber, manufactured by Teijin, trade name: TJ04CN, fineness: 1.1 dtex, after beating another pulper Fiber length: 5 mm) was mixed and dispersed in water and stored.

As the second surface layer, glass fiber / wood pulp / core-sheath type polyester composite fiber 1 is mixed at the entrance of the primary screen so that the content ratio is 40/51/9, and is sent to a long net to obtain a solid content of 80 g / to constitute a wet paper m ^2.

As the first surface layer, NBKP (wood pulp, trade name: Chinook, Canadian standard freeness 500 ml CSF) and PVA fiber (binder fiber, trade name: VPB107-1 × 3, manufactured by Kuraray Co., Ltd.) 90 After being mixed and dispersed so as to have a content ratio of / 10, it was stored and sent to a circular net to constitute a wet paper having a solid content of 10 g / m ² .

Wet paper composed of a long net and wet paper composed of a circular net were stacked and dried with a Yankee dryer having a surface temperature of 135 ° C. to produce a paper having a total basis weight of 90 g / m ² .

  Delami clay (Nu clay, manufactured by Engelhardt) is mixed with water, 0.1% by mass of a dispersant (sodium hexametaphosphate) is added, and after stirring for 30 minutes, a dispersed clay with a concentration of 65% by mass is prepared and stored in a storage tank. Stored with stirring. Polyvinyl alcohol (trade name: Gohsenol (registered trademark) NM-11, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) is mixed with water and heated to 90 ° C. with stirring to prepare a polyvinyl alcohol solution having a concentration of 12% by mass. And stored in a tank.

  The dispersion clay, the polyvinyl alcohol solution, and the acrylate copolymer were mixed so as to have a solid content of 70/10/20 to prepare a concentration of 48%.

On the second surface layer of the paper, the above coating liquid is applied at a solid content of 18 g / m ² by gravure coater offset coating and dried to produce a backing paper for flooring with a total basis weight of 108 g / m ^2. did.

Example 2
Dispersion of glass fibers (9 μm × 6 mm, manufactured by Asahi Fiber) was performed as follows. In the pulper, water and a nonionic surfactant (trade name: Nonion NS-206, manufactured by NOF Corporation, 2% by mass of glass fiber) as an initial dispersant were added and stirred, then glass fiber was added and stirred for 15 minutes. . Thereafter, 4% by mass of glass dispersion (trade name: SN Dispersant 5034, manufactured by San Nopco) was added as a dispersion stabilizer, and then an aqueous solution of polymer polyacrylamide (trade name: Acrypers PNS, manufactured by Mitsubishi Rayon) was added to glass fiber 1. 0 mass% (solid) was added, and the mixture was stored in a state of being stirred with a reciprocating rotary stirrer (manufactured by Shimazaki Seisakusho).

  NBKP (wood pulp, trade name: Chinook, Canadian standard freeness 500 ml CSF) and core-sheath type polyester composite fiber 1 (binder fiber, manufactured by Teijin, trade name: TJ04CN, fineness: 1.1 dtex, after beating another pulper Fiber length: 5 mm) and PVA fiber (binder fiber, trade name: VPB107-1 × 3, manufactured by Kuraray) were mixed and dispersed in water and stored.

As the second surface layer, glass fiber / wood pulp / core-sheath type polyester composite fiber 1 / PVA fiber is mixed at the entrance of the primary screen so as to have a content ratio of 40/50/8/2, and sent to the long net. A wet paper having a solid content of 80 g / m ² was constructed. Other than that was carried out similarly to Example 1, and produced the backing paper for flooring materials.

Example 3
Backing for flooring in the same manner as in Example 2 except that the content ratio of glass fiber / wood pulp / core-sheath polyester composite fiber 1 / PVA fiber in the second surface layer was changed to 40/50/5/5. Paper was made.

Example 4
Backing for flooring in the same manner as in Example 2 except that the content ratio of glass fiber / wood pulp / core-sheath polyester composite fiber 1 / PVA fiber in the second surface layer was changed to 40/50/3/7. Paper was made.

Example 5
Backing for flooring in the same manner as in Example 2 except that the content ratio of glass fiber / wood pulp / core-sheath polyester composite fiber 1 / PVA fiber in the second surface layer was changed to 40/50/2/8. Paper was made.

Example 6
The core-sheath polyester composite fiber 1 is changed to a core-sheath polyester composite fiber 2 (binder fiber, manufactured by Unitika, trade name: Melty (registered trademark) 4080, fineness: 2.2 dtex, fiber length: 5 mm), and the second surface layer A backing paper for flooring was produced in the same manner as in Example 2 except that the content ratio of glass fiber / wood pulp / core-sheath polyester composite fiber 2 / PVA fiber was changed to 40/50/5/5. .

Example 7
Glass fiber in the same manner as in Example 6 except that the content ratio of glass fiber / wood pulp / core-sheath polyester composite fiber 2 / PVA fiber in the second surface layer was changed to a ratio of 40/50/8/2. Mixed paper was prepared.

Comparative Example 1
Dispersion of glass fibers (9 μm × 6 mm, manufactured by Asahi Fiber) was performed as follows. In the pulper, water and a nonionic surfactant (trade name: Nonion NS-206, manufactured by NOF Corporation, 2% by mass of glass fiber) as an initial dispersant were added and stirred, then glass fiber was added and stirred for 15 minutes. . Thereafter, 4% by mass of glass dispersion (trade name: SN Dispersant 5034, manufactured by San Nopco) was added as a dispersion stabilizer, and then an aqueous solution of polymer polyacrylamide (trade name: Acrypers PNS, manufactured by Mitsubishi Rayon) was added to glass fiber 1. 0 mass% (solid) was added, and the mixture was stored in a state of being stirred with a reciprocating rotary stirrer (manufactured by Shimazaki Seisakusho).

  NBKP (wood pulp, trade name: Chinook, Canadian standard freeness of 500 ml CSF) and PVA fiber (binder fiber, trade name: VPB107-1 × 3, manufactured by Kuraray) are mixed and dispersed in water after beating another pulper. Stored.

As the second surface layer, glass fiber / wood pulp / PVA fiber is mixed at the entrance of the primary screen so as to have a content ratio of 40/50/10, sent to a long mesh, and wet paper having a solid content of 80 g / m ² . Configured. Other than that was carried out similarly to Example 1, and produced the backing paper for flooring materials.

Comparative Example 2
Dispersion of glass fibers (9 μm × 6 mm, manufactured by Asahi Fiber) was performed as follows. In the pulper, water and a nonionic surfactant (trade name: Nonion NS-206, manufactured by NOF Corporation, 2% by mass of glass fiber) as an initial dispersant were added and stirred, then glass fiber was added and stirred for 15 minutes. . Thereafter, 4% by mass of glass dispersion (trade name: SN Dispersant 5034, manufactured by San Nopco) was added as a dispersion stabilizer, and then an aqueous solution of polymer polyacrylamide (trade name: Acrypers PNS, manufactured by Mitsubishi Rayon) was added to glass fiber 1. 0 mass% (solid) was added, and the mixture was stored in a state of being stirred with a reciprocating rotary stirrer (manufactured by Shimazaki Seisakusho).

  NBKP (wood pulp, trade name: Chinook, Canadian standard freeness 300 ml CSF) and core-sheath type polyester composite fiber 2 (binder fiber, manufactured by Unitika, trade name: Melty (registered trademark) 4080, fiber after beating another pulper (Diameter: 2.2 dt, fiber length: 5 mm) were mixed and dispersed in water and stored.

As the second surface layer, glass fiber / wood pulp / core-sheath type polyester composite fiber 2 is mixed at the entrance of the primary screen so as to have a content ratio of 80/10/10, and is sent to a long screen to obtain a solid content of 80 g / to constitute a wet paper m ^2. Other than that was carried out similarly to Example 1, and produced the backing paper for flooring materials.

Comparative Example 3
As the second surface layer, glass fiber / wood pulp / core-sheath polyester composite fiber 2 is mixed at the entrance of the primary screen so as to have a content ratio of 75/10/15, sent to a long net, and a solid content of 80 g / to constitute a wet paper m ^2. Otherwise, the backing paper for flooring was produced in the same manner as in Comparative Example 2.

  Table 1 shows the fiber content ratios of the second surface layer and the first surface layer of the backing paper for flooring in each example and comparative example.

  Table 2 shows the results of surface flatness, peel strength, and tear strength.

  The backing papers for flooring materials of Examples 1 to 7 all have a tear strength of 3000 mN or more, there is no fear of paper breakage in the foamed vinyl chloride sol coating process, and the surface flatness is 3 or less, which is good. there were. In the backing papers for flooring materials of Examples 2 to 6, the surface flatness was improved to 2 by using a core-sheath polyester composite fiber and a PVA fiber as binder fibers.

  The backing paper for flooring of Comparative Example 1 has a tear strength of preferably 3000 mN or more because the second surface layer does not contain the core-sheath polyester composite fiber, but was less than 3000 mN.

  Although the backing paper for flooring of Comparative Examples 2 and 3 contains a core-sheath type polyester composite fiber, since the content ratio is 10% by mass or more, since the clogging is reduced, the surface flatness is low. It was a bad result.

  The backing paper for flooring of the present invention can be suitably used as a backing material for a flooring having a foamed polyvinyl chloride layer.

Claims (3)

  In the backing paper for flooring comprising glass fiber, wood pulp and binder fiber, the first surface layer is a layer containing wood pulp and not containing glass fiber, and the second surface layer is glass fiber, wood pulp And a binder fiber-containing layer, the second surface layer contains a core-sheath type polyester composite fiber as a binder fiber, and the content ratio of the core-sheath type polyester composite fiber with respect to all the fibers of the second surface layer Is a backing paper for flooring, characterized by having a coating layer on the second surface layer side.   The backing paper for flooring according to claim 1, wherein the second surface layer further contains polyvinyl alcohol fibers as binder fibers.   The backing paper for flooring according to claim 2, wherein the content ratio of the polyvinyl alcohol fiber is 1% by mass or more and less than 10% by mass with respect to all the fibers of the second surface layer.