JPH06278250A - Composite sheet - Google Patents

Abstract

PURPOSE:To provide a composite sheet for manufacturing easily a synthetic resin coated board free from pin holes which has good waterproof, chemical resistance, and surface smoothness. CONSTITUTION:A composite sheet for manufacturing a synthetic resin coated board comprising a nonwoven fabric, an adhesive polyolefine layer, a lower melting point polypropylene layer, and a higher melting point polypropylene layer, in which the adhesive polyolefin layer in particular is formed by extrusion.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water resistant material used for synthetic resin coated plates used for construction / construction members, furniture, etc.
The present invention relates to a composite sheet having excellent chemical resistance, corrosion resistance and surface smoothness.

[0002]

2. Description of the Related Art Conventionally, wood, wood plywood, particle board, fiber board, resin board, etc. have been used as a substrate, and a synthetic resin coating having excellent water resistance, chemical resistance, corrosion resistance and surface property is formed on the surface thereof. As a method, coating of a paint, laminating a film with an adhesive, and the like are performed. However, in these methods, the process for applying the adhesive is complicated, the equipment cost and the processing cost are also high, and furthermore, the pollution due to the solvent or the waste liquid in the adhesive, the deterioration of the working environment, the lack of adhesiveness, There were problems such as pinholes. Furthermore,
There is a problem in the durability of the synthetic resin coating layer because the surface layer may be lifted or peeled off depending on the impact received from the outside during use as various synthetic resin coated plates and the use environment.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a composite for a synthetic resin-coated plate which can easily produce a synthetic resin-coated plate having no pinhole and having excellent water resistance, chemical resistance and surface smoothness. It is an object of the present invention to provide a sheet, and more particularly, to provide a composite sheet capable of producing a synthetic resin-coated plate simultaneously with the production of the plywood during the production of the synthetic resin-coated plywood.

[0004]

[Means for Solving the Problems] The above-mentioned problems are solved by a composite sheet for synthetic resin coated plate comprising a nonwoven fabric, an adhesive polyolefin layer, a low melting point polypropylene layer and a high melting point polypropylene layer, particularly a low melting point polypropylene layer and a high melting point polypropylene layer. A two-layer film is used as the above, and the adhesive polyolefin layer is solved by a composite sheet for a synthetic resin coated plate formed by a melt extrusion method.

The present invention will be described in detail below. [Nonwoven fabric] The nonwoven fabric used in the present invention is required to have good adhesiveness with an adhesive polyolefin and also good adhesion with an adhesive for plywood adhesion. These adhesives also have a so-called anchor effect in which an adhesive polyolefin or an adhesive for bonding plywood is incorporated into the nonwoven fabric, but those having a polar group such as a hydroxy group, an ester group, or an amide group have a strong adhesive force and are desirable. . Examples of materials that satisfy these conditions include polyester, cellulose, cellulose acetate, and polyamide, with cellulose being particularly desirable. Further, these non-woven fabrics may contain various additives for enhancing the strength and water resistance of the non-woven fabric, if necessary.

[Adhesive Polyolefin] There are various adhesive polyolefins to be used in the present invention. Usually, carboxylic acid groups (acetic acid group, acrylic acid group, methacrylic acid group, fumaric acid group, Itaconic acid group, etc., Carboxylic acid metal base (sodium salt, calcium salt, magnesium salt, zinc salt, etc.), Carboxylic acid ester group (methyl ester group, ethyl ester group, propyl ester group, butyl ester group, vinyl ester group) Etc.), an acid anhydride group (maleic anhydride group, etc.) and an epoxy group, and a modified polyolefin having at least one kind of functional group.

Specific examples of such adhesive polyolefins include ethylene / acrylic acid copolymers and ethylene / acrylic acid copolymers.
Methacrylic acid copolymer, ethylene / fumaric acid copolymer,
Ethylene / methacrylic acid / zinc methacrylate copolymer,
Ethylene / acrylic acid / sodium methacrylate copolymer, ethylene / isobutyl acrylate / methacrylic acid /
Zinc methacrylate copolymer, ethylene / methyl methacrylate / methacrylic acid / magnesium methacrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene /
Vinyl acetate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, maleic anhydride grafted polyethylene, acrylic acid grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted polypropylene, fumar Acid-grafted polypropylene, maleic anhydride-grafted ethylene / propylene copolymer, acrylic acid-grafted ethylene / propylene copolymer, fumaric acid-grafted ethylene / 1-butene copolymer, ethylene / 1-
Hexene / itaconic acid copolymer, ethylene / propylene / endobicyclo [2.2.1] -5-heptene-2,
3-dicarboxylic anhydride copolymer, ethylene / propylene / glycidyl methacrylate copolymer, maleic anhydride grafted ethylene / propylene / 1,4-hexadiene copolymer, fumaric acid grafted ethylene / propylene / dicyclopentadiene copolymer , Maleic acid-grafted ethylene / propylene / norbornadiene copolymer, acrylic acid-grafted ethylene / vinyl acetate copolymer, etc. These modified polyolefins may be used alone or in combination of two or more kinds. Is.

Among these adhesive polyolefins, a graft polymer obtained by modifying polypropylene with an acid anhydride and having a melting point of 133 to 163 ° C. is desirable, preferably a melting point of 135 to 150 ° C., more preferably a melting point of 1
A modified graft polymer of a propylene ethylene random copolymer having a temperature of 35 to 145 ° C. is suitable. Melting point 133 ° C
If it is less than the above range, the heat resistance of the resulting composite sheet is insufficient, and bubbles are generated between the low melting point polypropylene layer and the low melting point polypropylene layer due to heating during bonding to the plywood, which is not preferable. Further, if the melting point exceeds 163 ° C., the laminating adhesive strength with the polypropylene layer tends to be low, which is not preferable.

The degree of polymerization of the adhesive polyolefin used in the present invention is not particularly limited, but it is usually a melt flow rate (hereinafter abbreviated as MFR, but the measurement conditions are JIS-
K-1410 condition 14) is 0.01 to 100 g.
/ 10 minutes can be arbitrarily selected within the range,
0.1 to 20 g / 10 minutes is preferable, and especially 1 to 15 g /
10 minutes is optimal.

In the adhesive polyolefin used in the present invention, generally used stabilizers for oxygen, heat and ultraviolet rays, that is, antioxidants, weathering agents, etc., processability improvers, fillers, pigments, etc. And additives such as processability-improving resin, tackifying resin and softening resin may be blended within a range that does not impair the purpose of the adhesive polyolefin.

[Polypropylene Layer] The polypropylene layer used in the present invention comprises a low melting point polypropylene layer and a high melting point polypropylene layer of two kinds and two layers using two kinds of polypropylene having different melting points. The two types of polypropylene having different melting points can be selected from propylene homopolymer, propylene ethylene random copolymer, propylene ethylene block copolymer and the like. The low-melting polypropylene layer is preferably a propylene-ethylene random copolymer which is located between the adhesive polyolefin layer and the high-melting polypropylene layer and has a melting point close to that of the adhesive polyolefin. As the melting point of the low melting point polypropylene becomes higher than the melting point of the adhesive polyolefin, the compatibility of the interface between the two during extrusion lamination becomes worse and the laminating adhesive strength tends to decrease. The melting point of the propylene ethylene random copolymer is preferably 150 ° C or lower, and preferably 145 ° C or lower.

The high melting point polypropylene layer has a high melting point,
A propylene homopolymer having good heat resistance is suitable, and the melting point is preferably 159 ° C. or higher. If the melting point is low, it is necessary to perform extrusion lamination at a high temperature to obtain high laminating adhesiveness during extrusion lamination of composite sheets, and at the time of bonding the composite sheets at a high temperature to increase the cycle of the process when laminating plywood. Since it is necessary to cure the agent, the transparency and smoothness of the polypropylene layer are reduced and the appearance is impaired.

The polypropylene layer used in the present invention is
It is composed of a low melting point polypropylene layer of two kinds and two layers and a high melting point polypropylene layer using two kinds of polypropylenes having different melting points, and a coextrusion molding film of two kinds and two layers is generally used. For the extrusion molding of the film, either a T-die film molding machine or an inflation film molding machine may be used, and the cooling system may be either roll cooling, water cooling or air cooling. From the viewpoint of transparency and smoothness of the film, a casting film produced by using a T-die film roll cooling molding machine is preferable.

In the polypropylene layer, in addition to the commonly used stabilizers for oxygen, heat and ultraviolet rays, processability improving agents, lubricants, fillers, pigments, etc., a clarifying agent,
Additives such as a slip agent, an antiblocking agent, an antistatic agent, and a release property imparting agent, and a pigment may be blended in a necessary layer as needed. Further, the surface of the polypropylene layer may be subjected to a pretreatment such as a corona discharge treatment or an anchor coat treatment, if necessary.

[Thickness] The thickness of the composite sheet of the present invention is the total thickness of the nonwoven fabric, the adhesive polyolefin layer and the polypropylene layer. However, since the adhesive polyolefin permeates the nonwoven fabric, the actual total thickness is reduced. If the total thickness is too thin, the durability as a surface protective layer of plywood is poor,
If the total thickness is too thick, the cost becomes high, which is not preferable. The thickness of the non-woven fabric is rarely shown, and generally, it is often shown by the weight per unit area (referred to as unit weight). That is, the basis weight of the nonwoven fabric is preferably 10 to ²⁰⁰ g / m ² . More preferably, the basis weight is 20 to 80 g / m ² . When the basis weight is less than 10 g / m ^2, it is difficult to control the penetration of the laminate resin and the adhesive, and it is quite difficult to obtain sufficient bonding strength to the plywood, and at the same time the nonwoven fabric is cut or laminated. Since there is a lot of show-through of resin, it is difficult to obtain the optimum composite sheet. Further, when the basis weight exceeds 200 g / m ² , the penetration of the laminate resin and the adhesive will be insufficient and the bonding strength to the plywood will not be sufficient, and more resin will be bonded to obtain the optimum penetration. An agent is required, resulting in high cost, which is not preferable. The thickness of the adhesive polyolefin is preferably 10 to 150 μm. More preferably, the thickness is 20 to 80 μm. If the thickness of the adhesive polyolefin is less than 10 μm, sufficient adhesiveness between the nonwoven fabric and the polypropylene layer cannot be obtained. Also,
If it exceeds 150 μm, the cost becomes high, which is not preferable. The thickness of the polypropylene layer is preferably 10 to 150 μm.
More preferably, the thickness is 20 to 80 μm. If the thickness of the polypropylene layer is less than 10 μm, the durability of the surface protective layer of the plywood is poor, which is not preferable. Also, the thickness is 150
If it exceeds μm, the cost becomes high, which is not preferable. further,
Of the two polypropylene layers, the ratio of the thickness of the high melting point surface layer to the thickness of the entire polypropylene layer is 20 to
95% is preferable. More preferably the ratio is 50 to 90%
Is. If it is less than 20%, the durability as the surface protective layer of the plywood is poor, which is not preferable, and if it exceeds 95%, it is difficult to obtain a two-layer film having a uniform ratio, which is not preferable.

[Lamination] In order to produce the composite sheet of the present invention, an extrusion laminating method is preferable, and for laminating a non-woven fabric which is difficult to apply an adhesive due to its fibrous surface to a thermoplastic resin layer. The sandwich method of extrusion laminating is most suitable. For the extrusion laminate, a general extruder and laminator can be used, for example, 30 to 300 m.
The adhesive polyolefin layer is melt-extruded on one side of the nonwoven fabric supplied at a rate of 1 / min, and the polypropylene layer is further supplied so as to sandwich the adhesive polyolefin layer, and pressure bonding is performed between the cooling roll and the pressing roll, so-called sandwich. There is a method of performing extrusion lamination of a method and winding the finished composite sheet into a roll.

The melt extrusion temperature of the adhesive polyolefin is
It is generally 200 to 330 ° C, and particularly preferably 250 to 320 ° C immediately below the die. If the temperature is lower than 200 ° C, the penetration of the adhesive polyolefin into the non-woven fabric is deteriorated and the effect of fusing with the polyolefin layer is reduced, which is not preferable. On the other hand, if the temperature exceeds 330 ° C., the decomposition reaction of the adhesive polyolefin becomes vigorous and stable extrusion lamination becomes difficult, which is not preferable.

In the present invention, ozone gas is blown to both surfaces of the adhesive polyolefin layer in the air-gap until the molten film of the adhesive polyolefin extruded from the T-die contacts the nonwoven fabric and the low melting point polypropylene layer. A method of increasing the laminating adhesive force between the adhesive polyolefin layer and the non-woven fabric and between the adhesive polyolefin layer and the low melting point polypropylene layer may be adopted. In addition, the adhesive surface of the non-woven fabric and the low melting point polypropylene layer is subjected to pretreatment such as corona discharge treatment and anchor coat treatment to increase the laminating adhesive force between the non-woven fabric and the adhesive polyolefin layer and between the low melting point polypropylene film and the adhesive polyolefin layer. You may take the method of making it.

The surface finish roughness of the cooling roll may be any of matte finish, semi-matte finish and mirror finish, and matte or semi-matte finish is more preferable in order to prevent wrinkles of the polypropylene layer. There are various types of surface rubbers such as silicone rubber and neoprene rubber, and any of them may be used.However, depending on the pressing force, the adhesive polyolefin may exude from the fiber gap of the non-woven fabric. It is desirable to use a silicone rubber or Teflon tape / Teflon sheet coated with good peeling property. Further, since the pressing force of the pressing roll largely influences the degree of penetration of the adhesive polyolefin into the nonwoven fabric, it is preferable to set an appropriate pressing force. If the pressing force is weak, there is little penetration of the adhesive polyolefin between the non-woven fabric fibers, and sufficient laminating adhesive force may not be obtained, which is not preferable. If the pressing force is strong, there is a large amount of permeation of the adhesive polyolefin between the non-woven fabric fibers, which impedes the permeation of the adhesive used when the composite sheet is bonded to the plywood into the non-woven fabric, resulting in sufficient plywood adhesion of the composite sheet. May not be obtained, which is not preferable.

[Laminating Process] The composite sheet obtained in the present invention is particularly preferably used for the production of synthetic resin-coated plywood. That is, when the composite sheet obtained by the present invention is press-formed at the same time when the wooden boards laminated with the adhesive are press-formed at the time of manufacturing the plywood, the composite sheet is bonded to the plywood at the same time by one press-forming. A synthetic resin-coated plywood can be manufactured.

The adhesive used between the wood board and the composite sheet is not particularly limited as long as it has an adhesive function under the press-molding conditions of plywood. For example, melamine resin, urea resin,
Thermosetting resins such as phenol resin, resorcin resin, furan resin and epoxy resin and thermoplastic resins such as polyacetic acid resin can be used, and particularly melamine-urea resin and melamine-
Phenolic resins are preferred.

[0022]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. The interlayer adhesion and concrete peeling property in the examples and comparative examples were evaluated as follows. (1) Adhesion between layers: Synthetic resin coated plate is manufactured and 2.5 cm
A sample of x30 cm was cut out, the polypropylene layer was peeled from the adhesive polyolefin layer with a width of 1 cm, and the peel strength was measured by a tensile tester. At that time, the peeling angle was 90 degrees and the peeling speed was 50 mm / min. A composite sheet having a peel strength of 700 g / cm or more is suitable. (2) Removability of concrete: Synthetic resin coated plate is manufactured,
Two pieces of 20 cm × 20 cm sample are cut out, and an appropriate amount of raw concrete is sandwiched between the surfaces of the synthetic resin, which are vertically aligned, to dry and cure the concrete indoors. The synthetic resin-coated plate was peeled from the sufficiently dried and hardened concrete, and the peelability and the adhesion of concrete to the surface of the synthetic resin were confirmed. ○: The synthetic resin coated plate easily peeled off from the concrete,
No concrete adhered to the synthetic resin surface. X: The synthetic resin coated plate is easily peeled off from the concrete, but the concrete has adhered to the surface of the synthetic resin. Must be ○.

Example 1 As the non-woven fabric, a cellulosic non-woven fabric having a basis weight of 40 g / m ² (“Benrise” manufactured by Asahi Kasei Kogyo Co., Ltd.) was used, and as the polypropylene layer, two polypropylenes having melting points of 160 ° C. and 135 ° C. were used. Using an extruded 50 μm casting film, the adhesive polyolefin has a density of 0.91 g / cm ³ , MFR of 12 g / 10 minutes, and a melting point of 13
A modified polypropylene having a maleic anhydride content of 0.2% by weight at 5 ° C. was melt-extruded and sandwich laminated to obtain a composite sheet. The extrusion of the adhesive polyolefin was performed under the conditions of a resin temperature of 290 ° C., a laminating speed of 60 m / min, and a thickness of 50 μm using an extruder having a diameter of 90 mm and L / D = 32. The pressing roll was used by pressing a Teflon tube having a thickness of 0.5 mm around neoprene rubber with an air pressure of 5 kg / cm ² .

Melamine-urea resin adhesive is applied to plywood 15
It was applied at 0 g / m ² and pressed so that the non-woven fabric surface of the composite sheet was in contact with the adhesive for 15 minutes at room temperature, then transferred to a heating press machine and pressed at 120 ° C. for 4 minutes to obtain a synthetic resin-coated plywood. It was As a result of evaluating the interlayer strength and the concrete peeling property of the obtained synthetic resin-coated plywood, good results were obtained without any problems. The results are shown in Table 1.

Example 2 As an adhesive polyolefin, the density is 0.91 g / cm.
³ , a composite sheet was obtained in the same manner as in Example 1 except that a modified polypropylene having an MFR of 10 g / 10 minutes, a melting point of 148 ° C. and a maleic anhydride content of 0.2 wt% was melt-extruded to obtain a composite sheet. A synthetic resin-coated plywood was obtained in the same manner as in. As a result of evaluating the interlayer strength and the concrete peeling property of the obtained synthetic resin-coated plywood, good results were obtained without any problems.

Comparative Example 1 A sandwich sheet was formed in the same manner as in Example 1 except that a 50 μm single-layer casting film of polypropylene having a melting point of 160 ° C. was used as the polypropylene layer to obtain a composite sheet. A synthetic resin-coated plywood was obtained. As a result of evaluating the interlayer strength and the concrete peelability of the obtained synthetic resin-coated plywood, the concrete peelability was good, but the interlayer strength was 390 g / cm and there was a problem in strength.

Comparative Example 2 A composite sheet was obtained by carrying out sandwich laminate molding in the same manner as in Example 1 except that a 50 μm single-layer casting film of polypropylene having a melting point of 135 ° C. was used as the polypropylene layer. A synthetic resin-coated plywood was obtained. As a result of evaluating the interlayer strength and the concrete peelability of the obtained synthetic resin-coated plywood, the interlayer strength was good, but the concrete peelability was poor, which is not preferable.

[0028]

[Table 1]

[0029]

EFFECTS OF THE INVENTION Suitable for synthetic resin coated plate, excellent in water resistance, chemical resistance, corrosion resistance and surface smoothness, and also excellent in concrete peelability, for strong synthetic resin coated plate with interlayer strength. A composite sheet of was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Mogi 3-2 Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Akira Kawasaki Plastic Research Laboratory

Claims (2)

[Claims] 1. A composite sheet for a synthetic resin coated plate, which comprises a nonwoven fabric, an adhesive polyolefin layer, a low melting point polypropylene layer and a high melting point polypropylene layer. 2. A composite sheet for a synthetic resin coated plate according to claim 1, wherein a two-layer film is used as the low melting point polypropylene layer and the high melting point polypropylene layer, and the adhesive polyolefin layer is formed by a melt extrusion method. .