JP5111460B2 - Impregnated paper for flooring - Google Patents

Description

  The present invention relates to an impregnated paper for flooring used as a reinforcing material for plywood constituting the flooring.

  2. Description of the Related Art Conventionally, an architectural decorative board such as a flooring material is generally provided with a decorative sheet, an adhesive layer, and a plywood. In particular, veneer plywood is often used as the plywood in composite flooring flooring, but MDF (medium density laminated board) is used as the reinforcing material. However, when MDF is used as the reinforcing material, the cost is not only higher than the floor material composed of a single plywood, but it absorbs moisture and swells, and the floor surface is likely to be wavy. There is a problem that the property becomes worse and a problem with caster resistance.

  Therefore, as a reinforcing material, in addition to MDF, for example, a resin-impregnated paper cured layer (craft paper) having a thickness of about 60 to 300 μm as shown in Patent Document 1, or a phenol composite resin as shown in Patent Document 2 A prepreg impregnated with a liquid of the above, a fiber sheet coated with a synthetic resin liquid as shown in Patent Document 3, and a resin impregnated with a DAP (diallyl phthalate) resin as shown in Patent Document 4 The use of a resin-impregnated paper base impregnated with a cured impregnated paper layer or a melamine resin as disclosed in Patent Document 5 is disclosed.

  Such kraft paper is impregnated with a thermosetting resin such as phenol, melamine, or DAP on the base paper to maintain the impact resistance of the flooring and to cover the unevenness formed on the surface of the flooring However, the undulation is prevented from being formed. In addition, the impregnation rate of the impregnating solution is high, requiring a large amount of chemical solution, being uneconomical, and relying on these thermosetting resins for impact resistance, so there is a limit to cushioning properties and still impact resistance I have a problem with sex.

  Moreover, with the recent increase in demand for wood, the price of veneer has soared, making it difficult to obtain veneer plywood. Therefore, in order to reduce the manufacturing cost, relatively inexpensive Chinese-made veneer plywood has been used. However, Chinese-made veneer plywood is soft, has low impact resistance, and has poor surface properties. For this reason, conventional kraft paper with a thickness of about 0.3 mm cannot secure impact resistance as a flooring material and cannot cover unevenness formed on the surface of the flooring material. It is necessary to absorb the liquid, and the cost is becoming uneconomical.

  In addition, composite flooring that uses a veneer sliced from natural wood as the surface material lacks sound insulation, so when it is directly applied to the concrete surface in an apartment or apartment, there is a possibility that it will adversely affect the comfortability. Synthetic resin sheets such as polyolefin and vinyl chloride have recently been used in place of natural wood veneers because natural wood on the surface is prone to warp, crack and crack due to moisture absorption. However, since such a synthetic resin sheet is excellent in fracture resistance, if the delamination strength of the reinforcing material of the veneer plywood disposed immediately below is low, there is a drawback that once the peeling starts, the plywood continues to peel. The reinforcing material is required to have high delamination strength.

  In addition, when V-cut processing is applied to a flooring material using kraft paper with a thickness of about 0.3 mm as a reinforcing material, the veneer plywood itself can be seen, resulting in a poor appearance of the flooring material. It was. Therefore, a method of laminating two pieces of kraft paper with a thickness of about 0.3 mm is used, but there is a problem that the peel strength decreases on the laminating surface of the kraft paper and the processing steps increase. In order to improve the peel strength of these bonding surfaces, it is necessary to increase the amount of the impregnating liquid.

  Further, the conventional kraft paper has a problem that the impregnation property of resin or the like is poor, and particularly the permeation rate of the impregnating liquid is slow, causing a problem in terms of efficiency. Furthermore, since the impregnation amount of the impregnation liquid is excessively increased, there is a problem that it is difficult to obtain impact resistance necessary for use as a flooring material. Therefore, there are means such as increasing the freeness of the raw pulp in order to improve the impregnation property, lowering the press linear pressure and calender linear pressure in the paper making process, but only these means weaken the entanglement between the pulp fibers. As a result, the inter-fiber strength is lowered, the interlaminar strength as the flooring impregnated paper cannot be ensured, and it is difficult to ensure impact resistance.

  Furthermore, thermosetting resins that have been used to ensure impact resistance, especially melamine resins, in particular, contain formaldehyde, which causes sick house syndrome, and formaldehyde is removed from the environmental and safety aspects. Is desired.

JP 2007-77726 A JP 2003-314043 A JP 2002-172604 A JP 2006-46053 A JP 2000-302900 A

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is not to use formaldehyde that may cause sick house syndrome unlike conventional impregnated paper. An object of the present invention is to provide an impregnated paper that can be used as an impregnated paper for a flooring material even when the caster property, the interlaminar strength, and the delamination strength are improved and the impregnation amount (rate) is low.

The above object of the present invention consists of at least two layers, a front layer and a back layer. The disintegration freeness measured according to JIS-P8121 (1995) is 500 to 700 cc, and the rice measured according to JIS-P8118 (1998). A floor formed by applying or impregnating the impregnation ratio of the coating liquid to 30 to 65% on a paper base having a grammage of 130 to 600 g / m ² and a density of 0.4 to 0.85 g / cm ^3. a timber for impregnated paper, the coating solution contains at least a thermoplastic resin, are those not containing formaldehyde, also the thermoplastic resin Ri butadiene latex der, and the butadiene latex this there a carboxyl-modified SBR, 90 degree peel test values measured in conformity with JIS-K6854-1 (1999) is 200~1100g / 15mm It is achieved by providing a flooring impregnated paper, wherein.

  Further, the above object of the present invention is to impregnate flooring characterized in that the DuPont impact test value measured in accordance with JIS-K5600-5-3 (1999) is 0.2 to 0.9 mm. This is achieved more effectively by providing paper.

The above-described object of the present invention, the paper against the base material, the adhesive force was calculated from the maximum load value at the time of the peeling during or destroyed measured according to the tensile JAS plywood plane test at 1.0~3.0MPa And more effectively by providing an impregnated paper for flooring characterized in that the water absorption thickness expansion coefficient measured according to JIS-A 5905-6-9 (2003) is 10 to 35%. Achieved.

  According to the impregnated paper for flooring according to the present invention, at least a thermoplastic resin is used, a coating liquid containing no formaldehyde-containing resin is used, and a butadiene latex is used as the thermoplastic resin. In addition, the impact resistance, caster resistance, interlayer strength and delamination strength can be improved, so that even if the amount of impregnation is low (rate) without excessively impregnating the coating liquid, It can be used as an impregnated paper for materials.

  Hereinafter, the impregnated paper for flooring according to the present invention will be described in detail. The impregnated paper for flooring according to the present invention is not limited to the following embodiment, and it is needless to say that the configuration can be changed as appropriate without departing from the scope of the claims.

  The impregnated paper for flooring according to the present invention (hereinafter referred to as “the impregnated paper”) is obtained by applying or impregnating a coating liquid onto a paper substrate having three or four paper layers (hereinafter referred to as “impregnated coating”). ").

  The coating liquid used at this time contains at least a thermoplastic resin and does not contain a resin containing formaldehyde. Thus, sick house syndrome can be prevented by preventing the coating liquid from containing a melamine-based resin containing formaldehyde that may cause sick house syndrome.

  Examples of the thermoplastic resin contained in the coating liquid include rubber-based latex, SBR (styrene / butadiene copolymer), NBR (acrylonitrile / butadiene copolymer), MBR (methyl methacrylate / butadiene copolymer). Coalescence), CR (chloroprene polymer), NR (natural rubber latex), urethane resin latex and resin latex, acrylic, vinyl acetate, etc. and copolymers thereof, acrylic resin, urethane resin, PVA, etc. However, in order to obtain the desired impact resistance and caster resistance of the present application without containing a thermosetting resin, a butadiene-based latex is used as the coating liquid for the impregnated paper. Furthermore, among butadiene-based latexes, it is preferable to use carboxyl-modified SBR. As a result, the impact resistance and caster resistance of the impregnated paper can be improved without using a thermosetting resin, and the interlayer strength and delamination strength can be improved. Will be able to.

  In addition, the coating liquid used for the impregnated paper can be used in combination of two types of acrylic resin and carboxyl-modified SBR, but it is preferable to use carboxyl-modified SBR alone. Thereby, the quality of impact resistance and caster resistance of the impregnated paper is further improved, and desired interlayer strength can be easily obtained. That is, the 90 ° peel test value measured in accordance with JIS-K6154-1 (1999) (hereinafter referred to as “interlaminar peel strength”) can be set to 200 to 1100 g / 15 mm, and the interlaminar peel strength is improved. Can be made. In addition, when the delamination strength is less than 200 g / 15 mm, there are problems that the interlaminar strength decreases and caster properties are poor. On the other hand, producing an impregnated paper for flooring having an interlaminar peel strength exceeding 1100 g / 15 mm requires adjustment of the concentration of the coating liquid, resulting in poor workability and high cost. Moreover, the impact test value (henceforth "impact resistance value") measured based on the "DuPont impact test" of JIS-K5600-5-3 (1999) is 0.2-0. It can be 9 mm, more preferably 0.2 to 0.4 mm. If the impact resistance value is less than 0.2 mm, the impact cannot be absorbed, and the impregnated paper tends to break, so that it becomes difficult to use the impregnated paper as a flooring. On the other hand, if the impact resistance value exceeds 0.9 mm, the amount of dents becomes large, so that the surface strength as a flooring material cannot be maintained, and similarly, it becomes difficult to use the impregnated paper as a flooring material.

  In addition, when combining two types of acrylic resin and carboxyl-modified SBR, the impact resistance of the impregnated paper is such that the mixing ratio of these two types is acrylic resin: carboxyl-modified SBR = 72-79: 28-21 The caster resistance can be further improved. If the mixing ratio of the acrylic resin is less than 72%, it becomes difficult to satisfy the interlaminar strength and delamination strength of the impregnated paper after the paper substrate is impregnated with the coating liquid. The impact resistance value cannot be obtained, and it becomes difficult to use such impregnated paper as a flooring material. On the other hand, when the mixing ratio of the acrylic resin exceeds 79%, it is difficult to satisfy the caster resistance, impact resistance, interlayer strength, and delamination strength desired by the present application unless a thermosetting resin is contained. Become. Further, if the mixing ratio of the carboxyl-modified SBR is less than 21%, the fluidity and viscosity of the coating liquid are lowered, so that the coating liquid tends to soak into the paper layer of the paper substrate, and the production cost is reduced. Get higher. On the other hand, if the mixing ratio of the carboxyl-modified SBR exceeds 28%, the fluidity and viscosity of the coating liquid increase, so that the penetration of the coating liquid into the paper layer of the paper substrate tends to deteriorate, and this impregnation It becomes difficult to obtain the desired impact resistance of the paper, and the operability is also lowered.

  Furthermore, the glass transition temperature (Tg) of the acrylic resin and the carboxyl-modified SBR is preferably −55 to 50 ° C., more preferably 0 to 25 ° C. This makes it easier to obtain the impact resistance, caster resistance, interlayer strength, and delamination strength desired by the impregnated paper. In addition, it is not preferable that Tg is less than −55 ° C. because the mechanical stability is poor, and a film is formed and adhered to a roll or the like at the time of production, which adversely affects the production of the actual machine. On the other hand, when the Tg exceeds 50 ° C., the resin is hard, so that it is difficult to satisfy the desired impact resistance value of the present application.

  The thermoplastic resin used in the present invention is preferably not water-soluble but water-dispersible and forms an emulsion. The average particle size is preferably 90 to 400 nm, more preferably 180 to 230 nm. Thereby, it becomes easier to improve the impact resistance, caster resistance, interlayer strength, and delamination strength of the impregnated paper. In addition, when the average particle diameter is less than 90 nm, the dispersibility of the emulsion particles tends to deteriorate, the emulsion particles tend to aggregate, and the coating property of the coating liquid tends to deteriorate. On the other hand, when the average particle diameter exceeds 400 nm, the impregnation property of the coating liquid into the paper layer is deteriorated, which may cause a decrease in interlayer strength and delamination strength, as well as operability.

  The B-type viscosity of the thermoplastic resin used in the present invention is preferably 15 to 600 mPa · s, more preferably 70 to 100 mPa · s. As a result, the impact resistance and caster resistance of the impregnated paper are further improved, and the desired interlayer strength and delamination strength of the present application can be easily maintained. When the B-type viscosity is less than 15 mPa · s, the impregnation property of the coating liquid is improved, but the fixability to the paper base material is deteriorated, and the desired impregnation rate may not be obtained. On the other hand, when the B-type viscosity exceeds 600 mPa · s, the impregnation property of the coating liquid into the paper layer is deteriorated, which may cause a decrease in interlayer strength and delamination strength, as well as a decrease in operability.

  The impregnated paper is formed by impregnating and applying the above coating liquid to all layers of the paper substrate. At this time, the coating liquid is impregnated with a paper base material, that is, with an impregnation ratio of 30 to 65%, preferably 40 to 48% with respect to the basis weight of all layers of the paper base material. Is preferred. Thereby, the adhesive strength (hereinafter referred to as “interlayer strength”) calculated from the value of the maximum load at the time of peeling or breaking measured according to the JAS plywood plane tensile test is 1.0 to 3.0 MPa, more preferably. Is 1.5 to 2.5 MPa, and the water absorption thickness expansion coefficient (hereinafter referred to as “water absorption thickness expansion coefficient”) measured according to JIS-A5905-6-9 (2003) is 10 to 35%. The impregnated paper can be made more excellent in impact resistance, caster resistance, and interlayer strength.

  If the impregnation ratio of the coating liquid is less than 30%, the impregnated paper cannot obtain the desired interlayer strength, and delamination tends to occur. Therefore, the impregnated paper can be used as a flooring. It becomes difficult. On the other hand, when the impregnation rate of the coating liquid exceeds 65%, since the coating liquid is impregnated more than necessary, drying takes time, work efficiency is deteriorated, and production cost is increased. It is uneconomical.

  Further, when the interlayer strength is less than 1.0 MPa, delamination occurs and the base material breaks down, so that the impregnated paper cannot be used as a flooring material. On the other hand, if the interlayer strength exceeds 3.0 MPa, it is difficult to satisfy the desired impact resistance of the impregnated paper because the coating solution is excessively impregnated.

  Further, if the water absorption thickness expansion coefficient is less than 10%, it is considered that the resin is excessively impregnated, and thus the impregnated paper cannot satisfy a desired impact resistance value. On the other hand, if the water absorption thickness expansion coefficient exceeds 35%, it absorbs moisture and expands, making it difficult to use such impregnated paper as a flooring.

Next, the paper base material that forms the impregnated paper will be described in detail. The paper substrate used for the impregnated paper has three or four paper layers. Further, the paper base material forming the impregnated paper has a disaggregation freeness (hereinafter referred to as “disaggregation freeness”) measured in accordance with JIS-P8121 (1995) of 500 to 700 cc, preferably 600 to 670 cc, JIS-P8118. (1998) and adjusted so that the US basis weight (hereinafter referred to as “US basis weight”) is 130 to 600 g / m ² and the density is 0.4 to 0.85 g / cm ³ . This makes it easier to obtain the impact resistance, caster resistance, interlayer strength, and delamination strength desired by the impregnated paper.

  If the paper substrate has a disaggregation freeness of less than 500 cc, the impregnation property of the coating liquid becomes low, so that it is difficult to reach the desired impregnation ratio of the impregnating paper. There is a risk that the interlaminar strength and delamination strength of the paper will decrease. On the other hand, when the disaggregation freeness exceeds 700 cc, the paper base material is unsatisfactory, so that the coating liquid is not uniformly impregnated in the paper base material and impregnation of the coating liquid is hindered. Therefore, it becomes difficult to reach the desired impregnation rate of the coating liquid of the impregnated paper, and similarly, there arises a problem that the interlayer strength and the delamination strength are lowered.

In addition, the paper base material used for the impregnated paper has a rice basis weight of 130 to 600 g / m ² , more preferably 130 to 280 g / m ² . The desired impact resistance, caster resistance, and interlayer strength of the impregnated paper can be obtained. If the paper basis of the paper base is less than 130 g / m ² , the impact resistance will be reduced, making it difficult to use the impregnated paper as a flooring. On the other hand, if the paper basis weight of the paper substrate exceeds 600 g / m ² , the impregnating property of the coating liquid is lowered, which causes a problem that the interlayer strength is lowered.

Furthermore, the density of the paper substrate used in the present impregnated paper is preferably from 0.4~0.85g / cm ^3, more preferably 0.65~0.75g / cm ^3. When the density of the paper substrate is less than 0.4 g / cm ³ , the coating liquid is impregnated more than necessary, so that the impact resistance of the impregnated paper is reduced and drying takes time, and the work efficiency In addition to this, there is a problem that the manufacturing cost increases. On the other hand, when the density exceeds 0.85 g / cm ³ , the coating liquid is difficult to be impregnated. Therefore, if the thermosetting resin is not contained, it is difficult to satisfy the caster resistance desired by the present application.

  Furthermore, the peel strength of the paper substrate used for the impregnated paper is preferably 0.50 to 1.50 MPa, more preferably 1.00 to 1.50 MPa. If the peel strength of the paper substrate is less than 0.50 MPa, the interlaminar strength and delamination strength after coating or impregnation of the coating liquid will be reduced. On the other hand, even if the peel strength of the paper substrate exceeds 1.50 MPa, there is no change in quality, workability is deteriorated, and only the cost is increased.

  In addition, the raw material pulp of each layer constituting the paper base material used for the impregnated paper includes hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and softwood unbleached kraft. Pulp (NUKP), hardwood sulfite pulp, wood fiber such as coniferous sulfite pulp, the main raw material, chemically treated pulp, chemically treated pulp and ground pulp mechanically pulped chips, Thermo-mechanical pulp (TMP) in which chips are mechanically pulped under heating and pressure, Chemi-ground pulp mechanically pulped with chemicals added to wood or chips, and after cooking the chips until soft Virgin pulp such as semi-chemical pulp pulped with a refiner or the like can be used. In addition, non-wood fibers such as kenaf, hemp, and straw, which are fiber materials other than wood, can be used. However, non-wood pulp has low pulp strength and the unit price of the pulp itself is high. It is preferable to use mechanical pulp such as kraft pulp and TMP. In addition, pulp made from waste paper may be blended, but because there are many fine fibers, the drainage of the paper base material becomes worse, the production speed decreases, and the appearance of the paper after impregnating the paper base material with the resin is good. Deteriorates and the interlaminar strength also decreases. Therefore, it is preferable not to mix the waste paper pulp with the raw material pulp that forms the surface layer and the back layer, and it is more preferable not to mix it with the raw material pulp that forms the middle layer.

  Among these, especially the raw material pulp which comprises a paper base material shall use 50-90 mass% of the whole raw pulp as hardwood bleached kraft pulp (LBKP), and 10-50 mass% of softwood bleached kraft pulp (NBKP). Desirably, 10-40 mass% of NBKP is blended. When the blending ratio of NBKP exceeds 50% by mass, the texture becomes poor and the impregnation tends to be inferior. On the other hand, if the blending ratio of NBKP is less than 10% by mass, the desired interlaminar strength and delamination strength of the impregnated paper cannot be obtained, and delamination tends to occur. Therefore, the impregnated paper is used as a flooring. It becomes difficult. Moreover, it is more preferable to mix | blend mechanical pulp, such as TMP, with 0-20 mass% of the whole raw material pulp, especially 0-10 mass%. If the blending ratio of mechanical pulp such as TMP exceeds 20% by mass, the resin content peculiar to mechanical pulp increases, so the permeability of the thermoplastic resin tends to decrease, and the amount of impregnation of the desired coating liquid is reduced. It becomes difficult to secure. As a result, impact resistance, interlayer strength, and delamination strength may be reduced.

  Furthermore, since this impregnated paper is constituted by impregnating a resin with a paper base material, it is preferable to make each layer using raw pulp of the same composition, for example, mixing old paper in the raw pulp of the middle layer, etc. Papermaking may be performed using raw pulp having a different composition from the surface layer, middle layer and back layer.

  Moreover, it is preferable to add a wet paper strength enhancer and a dry paper strength enhancer to at least one layer of the raw material pulp of the paper substrate. Thereby, while being able to improve the workability at the time of the impregnation coating of a coating liquid, the interlayer intensity | strength of this impregnated paper can be made higher. In addition, when a wet paper strength enhancer is not added, when the coating liquid is impregnated and coated on a paper base material, the processing suitability may be lowered, for example, paper breakage may occur. On the other hand, when the dry paper strength enhancer is not added, the interlaminar strength of the impregnated paper after impregnating and applying the coating liquid to the paper base material is lowered, making it difficult to use the impregnated paper as a flooring. Therefore, it is more preferable to add a wet paper strength enhancer and a dry paper strength enhancer to the raw material pulp of all layers of the paper substrate.

  As such a wet paper strength enhancer, for example, polyamide polyamine / epichlorohydrin type, melamine / formalin type, urea / formalin type resin and the like can be used. Moreover, as a dry paper strength enhancer, anionic or cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan and the like can be used. However, the wet paper strength enhancer and the dry paper strength enhancer used for the impregnated paper are not limited to these.

  Moreover, since the impregnation property of the coating liquid for the paper base material is lowered by adding the paper strength enhancer, a sizing agent is added to the raw material pulp to which the paper strength enhancer is added. In addition to the sizing agent, it is also possible to add chemicals such as a liquid absorbing agent and a bulking agent in order to give the paper base material the impregnation property of the coating liquid. However, since it is not necessary to add chemicals such as a sizing agent depending on the degree of beating of the raw pulp and the blending ratio of the pulp, it may not be added in this case.

  In addition, about the addition amount, kind, etc. of the chemical | medical agent added to the raw material pulp of each layer which comprises a paper base material, it can adjust suitably.

  The raw material pulp described above forms a paper substrate having three or four paper layers through a known papermaking process, for example, a wire part, a press part, a dryer part, a size press, a calendar part, and the like. The paper making method of the paper substrate is not particularly limited, and any of acidic paper making method, neutral paper making method and alkaline paper making method may be used. Also, since the paper machine is not particularly limited, for example, various known paper machines such as a long net paper machine, a twin wire paper machine, a circular net paper machine, and a short net combination machine can be used. it can.

  The paper substrate thus formed preferably has a resin impregnation property of the coating liquid of 0.5 to 3.0 seconds, more preferably 0.7 to 1.2 seconds. When the resin impregnation property of the coating liquid is less than 0.5 seconds, there is a problem that the amount of the coating liquid impregnated becomes too large. On the other hand, if the resin impregnation property exceeds 3.0 seconds, the paper base material cannot be sufficiently impregnated with the coating liquid, so that it becomes difficult to use it as impregnated paper for flooring.

  As described above, the paper base used for the impregnated paper has been described with respect to the case where the paper base is composed of three or four paper layers. However, the present invention is not necessarily limited to such a paper base, and is formed with a multilayer paper structure. In addition, a base material composed of two paper layers, a front layer and a back layer, or a paper base material composed of five or more paper layers may be used. That is, in the floor material impregnated paper having an intermediate layer composed of a plurality of layers, all layers including the intermediate layer may be impregnated with the coating liquid.

As described in detail above, it contains a thermoplastic resin that is a butadiene-based latex (particularly carboxyl-modified SBR), and has a coating liquid that does not contain formaldehyde, at least two paper layers, a front layer and a back layer, By impregnating a paper substrate having a disaggregation freeness of 500 to 700 cc, a rice basis weight of 130 to 600 g / m ² and a density of 0.4 to 0.85 g / cm ³ , By making the impregnation ratio of the coating liquid with respect to the paper substrate 30 to 65%, the delamination strength is effectively 200 to 1100 g / 15 mm, the impact resistance value is 0.2 to 0.7 mm, The interlayer strength can be 1.0 to 3.0 MPa, and the water absorption thickness expansion coefficient can be 10 to 35%. That is, the impact resistance and caster resistance can be improved without using a thermosetting resin such as melamine resin containing formaldehyde in the coating liquid or a thermosetting resin such as phenol or DAP, and the present invention. The desired interlayer strength can be obtained, and sick house syndrome can be prevented. Further, even if the amount of impregnation is low (rate) without excessively impregnating the coating liquid, it can be used as impregnated paper for flooring.

  In order to confirm the effect of the impregnated paper for flooring according to the present invention, the following various samples were prepared, and a test for evaluating the quality of each sample was performed. In addition, in a present Example, the numerical value which shows a mixing | blending, a density | concentration, etc. is a numerical value of the solid content or the mass reference | standard of an active ingredient. Moreover, since the pulp, chemical | medical agent, etc. which are shown in a present Example are only examples, it cannot be overemphasized that this invention is not restrict | limited by these Examples, and can be selected suitably.

  Three types of impregnated paper for flooring according to the present invention (referred to as “Example 1” to “Example 33”) and these Examples 1 to 33 were compared with three types of impregnated paper. Impregnated paper for flooring (referred to as “Comparative Example 1” to “Comparative Example 3”) was prepared in the configurations shown in Tables 1 and 2.

[Example 1]
Using the following raw materials, a paper base material having a three-layer structure consisting of a surface layer, a back layer, and one middle layer located between both layers was obtained according to the following production method.
<Raw material>
-Surface layer and back layer After blending 90% by mass of hardwood bleached kraft pulp (LBKP) and 10% by mass of softwood bleached kraft pulp (NBKP), the disaggregation freeness measured according to JIS-P8121 (1995) becomes 600cc. The raw material prepared in this manner was made of aluminum sulfate (manufactured by Nippon Light Metal Co., Ltd., 8% liquid aluminum sulfate) in the form of 2.0% by mass (20 kg / t), wet paper strength agent (WS4024 manufactured by Seiko PMC Co., Ltd.) 0.5 mass% (5 kg / t) in solid form, and 0.4 wt% (4 kg / t) solid paper strength agent (DS4356 manufactured by Seiko PMC Co., Ltd.) in solid form, surface layer, middle layer and back layer A raw material pulp slurry was obtained. Using these raw material pulp slurries, the surface layer, the middle layer, and the back layer paper layer are made together by a circular paper machine, the surface layer weight is 46 g / m ² , and the middle layer weight is 48 g / m. A three-layer paper base having a basis weight of m ² , a backing layer of 46 g / m ² , and a basis weight of the entire paper base (US basis) of 140 g / m ² was obtained.
<Coating solution>
A coating solution for impregnating the paper substrate was prepared as shown in Table 1. That is, a coating liquid containing carboxyl-modified SBR (SR102 Tg: 21 ° C., manufactured by Nippon A & L Co., Ltd.) as a thermoplastic resin was obtained.
<Preparation of impregnated paper>
An impregnated paper (Example 1) is prepared by impregnating the above-mentioned coating liquid onto the paper base material at a ratio of 60% with respect to the paper base material using a dipping squeeze type impregnation machine.

  Further, impregnated papers were prepared in the same manner as in Example 1 except that Examples 2 to 33 and Comparative Examples 1 to 3 were the conditions shown in Tables 1 and 2. In addition, XP8806 (Tg: 0 ° C.) manufactured by Seiko PMC Co., Ltd. was used as the acrylate in the examples, and as an unmodified carboxyl SBR (in the table, “unmodified SBR”), manufactured by Nippon Zeon Co., Ltd. 2507H (Tg: 58 ° C.), NA-20 (Tg: −20 ° C.) manufactured by Nippon A & L Co., Ltd. was used as the modified NBR, and MR-171 (Tg: − manufactured by Nippon A & L Co., Ltd.) was used as the modified MBR. 30 ° C.). Further, as the MDF board in this comparative example, a commercially available 5.5 mm MDF board (melamine resin cured product) was sliced and adjusted to a thickness of 0.6 mm, and as a thermosetting resin melamine resin, Nippon Carbide Corporation. SW-260 made by Showa Polymer Co., Ltd. was used as the acrylate.

  Table 2 shows the results of quality evaluation of the impregnated papers of all Examples and Comparative Examples. This quality evaluation test was performed under environmental conditions of temperature 23 ± 2 ° C. and humidity 50 ± 2% in accordance with JIS-P8111.

  “Disaggregation freeness (cc)” in Table 1 refers to “paper and paperboard—pulp freeness test method—Canadian standard freeness test method” described in JIS-P8121 (1995). It is a measured value.

Further, “US basis weight (g / m ² )” is the basis weight of the entire paper base material used for all layers of each sample, that is, the impregnated paper for flooring, and “paper and paper” described in JIS-P8124 (1998). It is the value measured based on "paperboard-basis weight measuring method".

“Density (g / cm ³ )” refers to the basis weight measured in accordance with “Paper and paperboard—basis weight measurement method” described in JIS-P8124 (1998) and JIS-P8118 (1998). It is a value calculated from the paper thickness measured according to “Paper and paperboard—Test method of thickness and density”.

  “Peel strength (MPa)” is an evaluation of interlaminar strength, and is a value measured in accordance with “Paper and paperboard—Murlen high-pressure tester's burst strength test method described in JIS-P8131 (1995). It is.

  “Resin permeability (seconds)” is an evaluation of the liquid absorption time of the coating liquid. Instead of the kit 6 liquid used in the above oil absorption measurement method, carboxyl-modified SBR (manufactured by Nippon A & L Co., Ltd.) SR102 Tg: 21 ° C.).

  Further, “resin impregnation rate (vs. paper base material) (%)” in Table 2 indicates the amount of the coating liquid impregnated, and is the liquid absorption amount of the coating liquid with respect to the paper base material.

  The “impact resistance test (mm)” is an evaluation of the amount of dents, and the amount of dents measured according to the DuPont falling ball impact dent test specified in “Paint General Test Method” described in JIS-5600. (Mm) is measured. The measurement conditions were a drop weight of 710 g, a drop height of 30 cm, and a ball radius of 6.35 mm.

“Water absorption thickness expansion rate (%)” is an evaluation of dimensional stability in the Z-axis direction during water absorption. Calculated by the following (Equation 1) from the paper thickness of the paper base material before and after water absorption when immersed in normal temperature water for 24 hours by the method prescribed in the fiberboard of JIS-A5905 (2003). It is the value.
(Equation 1)
Water absorption thickness expansion rate (%) = ((paper thickness after water absorption−paper thickness before water absorption) / paper thickness before water absorption) × 100

  “Interlaminar strength (MPa)” was defined as the maximum load (MPa) at the time of peeling or breaking measured according to the JAS plywood plane tensile test.

  Further, the “delamination strength (g / 15 mm)” is an evaluation of delamination strength by a 90-degree peel test, and “adhesive-peel adhesion strength” described in JIS-K-6854-1 (1999). The peel strength measured in accordance with the 90-degree peel test specified in “Test Method” is measured. The measurement conditions were a test piece width (width direction) of 15 mm, a length (flow) of 150 mm or more, and a peeling rate of 100 mm / min.

From Table 2, it is excellent even if it does not mix | blend the thermosetting resin containing formaldehyde with a coating liquid as it is the impregnated paper for flooring which concerns on this invention, ie, the impregnated paper which concerns on Example 1-3. It can be seen that it has high impact resistance and caster resistance. Moreover, even if there are few amounts of impregnation of a coating liquid, it turns out that it is excellent in interlayer strength and delamination strength, and an impregnation paper can be used for a flooring.

Claims (3)

It consists of at least two layers, a front layer and a back layer. The disintegration freeness measured according to JIS-P8121 (1995) is 500 to 700 cc, and the rice floor measured according to JIS-P8118 (1998) is 130 to 600 g / m. ² is an impregnated paper for flooring formed by applying or impregnating an impregnation ratio of a coating liquid to a paper base having a density of 0.4 to 0.85 g / cm ³ to 30 to 65%. the coating solution contains at least a thermoplastic resin, are those not containing formaldehyde, also the thermoplastic resin Ri butadiene latex der, and, the butadiene latex is a carboxyl-modified SBR , flooring 90 degree peel test values measured in conformity with JIS-K6854-1 (1999) is characterized in that it is a 200~1100g / 15mm Impregnated paper. The impregnated paper for flooring according to claim 1, wherein a DuPont impact test value measured in accordance with JIS-K5600-5-3 (1999) is 0.2 to 0.9 mm. The adhesive strength calculated from the value of the maximum load at the time of peeling or breakage measured according to the JAS plywood plane tensile test with respect to the paper substrate is 1.0 to 3.0 MPa, and JIS-A 5905-6-9. The floor material impregnated paper according to claim 1 or 2 , wherein the water absorption thickness expansion coefficient measured according to (2003) is 10 to 35%.