JPS6116965A - Composite resin sheet - Google Patents

Abstract

PURPOSE:A composite resin sheet that contains a thermoplastic resin and wood flour and has a water content controlled lower than a specific value, thus being suitable for use in vacuum molding, because it causes no bubbling or tearing of molding and giving molded products with good surface appearance. CONSTITUTION:(A) 95-30wt%, preferably 90-40wt% of a thermoplastic resin such as polyolefin or vinyl chloride resin are mixed with (B) 5-70wt%, preferably 10-60wt% of a wood flour such as pine or oak flour or saw dust, preferably of less tha 60 mesh, after separately dried, further when needed, aninorganic filler, an antioxidant, an antistatic, then they are kneaded and pelletized. The resultant pellets are preferably dried, made into a sheet to give the objective composite resin sheet with less than 0.5wt% water content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a composite resin sheet as a molding material that allows molded products with good surface appearance to be obtained without foaming or tearing during molding.

[Conventional technology] Conventionally, in order to give plastic molded products the insulation, rigidity, and feel of wood, there has been a known technology for molding a composition of thermoplastic resin mixed with wood flour. .

[Problems to be Solved by the Invention] However, when a resin composition containing wood flour mixed with a thermoplastic resin is molded, foaming and tearing occur during processing, resulting in a molded product with poor appearance.

It is difficult to deep-draw the resin composition, and even if deep-drawing is attempted, it is difficult to form sharp corners in the molded product.Furthermore, the molding time until the desired deep-drawing is extended, resulting in poor overall performance. The disadvantage is that the molding cycle becomes longer.

[Means for solving the problem 1] Based on the above-mentioned circumstances, the inventors have developed a material that does not cause foaming or tearing during the molding process, has heat insulating properties, rigidity, and wood texture like wood, and has a good appearance. As a result of intensive research on thermoplastic resin materials containing wood flour that can be processed into molded products with
As a result, it was discovered that the molded product had a poor appearance, and the present invention was achieved.

That is, in this invention, the thermoplastic resin is 95 to 30% by weight.
This is a composite resin sheet characterized by containing 5 to 70% by weight of wood flour and 5 to 70% by weight of wood flour, and having a moisture content adjusted to 0.5% by weight or less.

As the thermoplastic resin in this invention, there are no particular limitations, and various kinds of resins can be used. Specifically, for example, polyolefin resins, vinyl chloride resins and copolymer resins thereof,
Engineering of general resins such as vinylidene chloride resin, polystyrene and its copolymer resins, methyl methacrylate resin, vinyl acetate resin, polyamide resin, polyacetal, polycarbonate, thermoplastic polyester resin, polyphenylene oxide and noryl resin, polysulfone, etc. One example is plastic.

Examples of the polyolefin resin include polyethylenes such as ultra-high density polyethylene, high-density polyethylene, medium- and low-density polyethylene, and linear low-density polyethylene;
Examples include polypropylene such as isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene, polybutene, and 4-methylpentene-1 resin. Copolymers of olefins and other vinyl monomers, such as ethylene vinyl chloride copolymers, propylene vinyl chloride copolymers, etc., can also be used.

Examples of the vinyl chloride copolymer resin include vinyl chloride vinyl acetate resin, vinyl chloride vinylidene chloride copolymer resin, and vinyl chloride acrylonitrile copolymer resin.

As the polystyrene copolymer resin, for example, A
Examples include BS resin, SAN resin, AC3 resin, and the like.

Examples of the methyl methacrylate resin include polymethacrylic esters such as polymethyl methacrylate, polyethyl methacrylate, poly-n-propyl methacrylate, polyisopropyl methacrylate, and polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, and poly-n-propyl methacrylate. - Polyacrylic acid esters such as propyl acrylate, polyisopropyl acrylate, and polybutyl acrylate can be mentioned.

Examples of the vinyl acetate resin include moldable synthetic resins derived from vinyl acetate resin, such as polyvinyl alcohol and polyvinyl formal.

Examples of polyamide resins include nylon 6, nylon 8. Nylon IT, +Iron 66, Nylon 610
etc.

The polyacetal may be a single polymer (Delrin) or a copolymer (Duracon).

Examples of the polycarbonate include polycarbonate obtained from bisphenol A and phosgene, and polycarbonate obtained from bisphenol A and diphenyl carbonate.

Examples of the thermoplastic polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and the like.

Since the thermoplastic resin in this invention is blended with wood flour to form a moldable composite resin sheet, if the thermoplastic resin has a moldable molecular weight,
The various thermoplastic resins mentioned above can be appropriately selected and used. The above various thermoplastic resins may be used alone, or two or more types may be mixed and used as a polymer blend. However, among the above various thermoplastic resins, polyethylene, polypropylene, etc. are preferable. These include polyolefin, polystyrene and its copolymer resin, polyamide, polycarbonate, etc., and particularly preferred are polyethylene, polypropylene, polystyrene, ABS resin, nylon 6, polycarbonate, etc.

Furthermore, when using a hygroscopic thermoplastic resin among the various thermoplastic resins mentioned above, it is preferable to dry and dehydrate it before blending it with wood flour.

As the wood powder, powder of wood such as pine or oak or sawdust can be used. Further, it is preferable that the wood flour has a mesh size of 60 mesh or less.

If the wood flour is larger than 60 meshes, the wood flour may be poorly dispersed in the thermoplastic resin, and the resulting molded product may have a poor appearance.

The blending amount of the thermoplastic resin and the wood flour should be 95 to 30% by weight of the thermoplastic resin and 5 to 70% by weight of the wood flour, particularly preferably 90 to 40% by weight of the thermoplastic resin,
The wood flour content is 10-60% by weight. If the wood flour content is less than 5% by weight, the resulting molded product will lack heat insulation, rigidity, and wood texture; if the wood flour content is more than 70% by weight, the resulting molded product will have a poor appearance and will be difficult to mold. Sometimes foaming or tearing occurs.

The composite resin sheet according to the present invention basically comprises the thermoplastic resin and the wood flour, but if necessary, an inorganic filler, an antioxidant, an antistatic agent, a flame retardant, a lubricant, etc.
It may also contain various additives such as colorants.

Examples of the inorganic filler include metal oxides such as magnesium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, 1&acid salts such as calcium sulfate and magnesium sulfate, and calcium sulfite. Sulfites, talc, clay, mica, asbestos, glass fiber, glass peas, calcium silicate,
Examples include silicates such as montmorillonite and bentonite, metal powders such as iron, zinc, and aluminum, ceramics such as silicon carbide and silicon nitride, and their whiskers, carbon black, graphite, and carbon fiber, and these inorganic fillers. These inorganic fillers can be used alone or in combination of two or more of the above inorganic fillers.

As the antioxidant, for example, amines, quinones, phenol compounds, sulfur compounds, phosphorus compounds, etc. can be used.

Examples of the antistatic agent include anionic surfactants such as pt-amylphenol lead, cationic surfactants such as polyoxyethylene alkylamine, and nonionic surfactants such as alkylphenol ethylene oxide adducts. Polymer surfactants, amphoteric surfactants such as carboxylic acid type metal salts, etc. can be used.

Examples of the flame retardant include halogenated flame retardants such as tetrabromobisphenol A1 chlorinated paraffin, ammonium phosphate, tricresyl phosphate, triethyl phosphate, tris(β-chloroethyl) phosphate, acidic phosphate, and nitrogen-containing phosphorus. Phosphorous flame retardants such as compounds, red phosphorus, tin oxide, antimony trioxide, zirconium hydroxide, barium metaborate, aluminum hydroxide, magnesium hydroxide, and other inorganic flame retardants can be used.

Examples of lubricants include hydrocarbon liquid paraffin,
Higher fatty acids such as natural paraffin and wax,
Oxyfatty acids, ester aliphatic alcohols, polyglycols, metal stearates such as calcium stearate, barium stearate, and other metal soaps, silicone oils, modified silicones, and other silicones can be used.

As the coloring agent, a poorly soluble azo dye, a red coloring agent, cadmium yellow, chrome yellow, titanium white, etc. can be used.

The amount of these additives to be added is appropriately determined as long as the amount of the thermoplastic resin is within the range of 95 to 30% by weight and the water content in the composite resin sheet does not exceed 0.5% by weight. can do.

The composite resin sheet according to the present invention is produced by mixing the thermoplastic resin and the wood flour using a mixer such as a ribbon blender, tumble mixer, Henschel mixer, etc. The thermoplastic resin and the wood flour are thoroughly mixed by a method of cross-mixing using a mixer such as a screw extruder or a single-shaft reciprocating screw mixer, or by a method of simultaneously performing a cross-mixing operation using each of the above-mentioned kneading machines. Then, it can be pelletized using, for example, a pelletizer, and the resulting pellets can be obtained by, for example, an extrusion molding method, a calender molding method, or the like. moreover,
The composite resin sheet is obtained by mixing and/or kneading a portion of the thermoplastic resin and the entire amount of the wood flour to obtain a mask resin composition, and then mixing the mask resin composition with the remaining amount of the thermoplastic resin. It can also be obtained by using pellets obtained by diluting the mask resin composition by mixing it with a resin.

The heating temperature during mixing or crossing depends on the type of thermoplastic resin used, but is usually in the range of about 180 to 230 degrees, and may be heated until the thermoplastic resin becomes plasticized.

In addition, the time required for mixing and kneading varies depending on the type of thermoplastic resin used and the type of mixer or kneader, but usually it is about t-15 minutes in the case of an extruder, and In this case, it will take about 5 to 20 minutes.

The heating temperature when forming the pellets into a sheet depends on the type of thermoplastic resin used, but is usually 1.
The range is about 80 to 230 degrees.

It is important that the composite resin sheet according to the present invention has a water content of 0.5% by weight or less when processed into a molded product. Therefore, the moisture content in this composite resin sheet is 0.
The thermoplastic resin and wood flour to be blended are each dried so that the content is 5% by weight or less, and the pellets obtained by blending the thermoplastic resin and wood flour are dried and then formed into a sheet. It is preferable that the moisture content of the wood flour used for blending is 10% by weight or less. When the moisture content of the wood flour blended into the thermoplastic resin exceeds 10% by weight, the moisture content in the resulting composite resin sheet is 0.5% by weight.
%, which may cause foaming or tearing during molding. In order to make the moisture content in wood flour 2.4% by weight, for example, if the wood flour is 100 mesh, it is about 5% by weight.
If the moisture content is , it is recommended to pre-dry at 150 degrees C for 1 to 5 hours.

In order to reduce the water content in this composite resin composition to 0.5% by weight or less, in addition to the above-mentioned method, a vent-type extruder may be used when producing pellets.

The composite resin sheet according to the present invention is molded into various plastic molded products by a blow molding method, a lamination molding method, a layer molding method, or the like.

[Effect of the invention] According to this invention, the moisture content in the composite resin sheet is reduced to 0.5
Since it is adjusted to less than % by weight, foaming during molding of this composite resin sheet is prevented, and the resulting molded product has no silver streaks, tears, etc. and has a beautiful appearance. can. Moreover, when deep drawing is performed using this composite resin sheet, the maximum drawing depth can be increased, and the corners of the molded product can be formed into sharp corners. In addition, the molding time up to deep drawing can be shortened, and the overall molding cycle can also be shortened.

Furthermore, since the molded product obtained by molding this composite resin sheet contains wood flour, it can have heat insulation properties, rigidity, and a woody feel like wood.

This composite resin sheet is suitable as a material for blow molding, and can be processed into acoustic parts such as player bottoms, home appliance parts, automobile interior materials, daily necessities, etc. by blow molding.

[Examples] Next, examples of the present invention and comparative examples thereof will be shown to further specifically illustrate the present invention.

(Examples 1 to 21, Comparative Examples 1 to 12) A thermoplastic resin of the type shown in Table 1, wood flour with a moisture content shown in the same table, and optionally an additive of the type shown in the table After premixing in the blending amounts shown in , pellets were obtained using a vented single-screw extruder [manufactured by Nakatani Kikai Co., Ltd., 50 mm diameter]. The heating temperature during pellet production is 180℃ for polyethylene, polypropylene, and ABS resin.
~200 degrees C and for polyamides 200-2
It is 30 degrees C. The vent was suctioned at 600 g. In addition, the wood flour in the examples had a moisture content of 5.15% and was made of lOO mesh and was dried at 150 degrees Celsius for 1 to 5 hours before use. Next, the vented T
A sheet with a thickness of 2 mm was produced from the pellets using a die extruder (manufactured by Nakatani Kikai Co., Ltd., width 500 mm, thickness 2 mm). In addition, the heating temperature during sheet production is 18°C for polyethylene, polypropylene, and ABS resin.
0 to 190 degrees C, and for polyamides 200 to
The temperature was 220 degrees C-t', and the vent was suctioned at 600 mm and 1 g.

The moisture content of the sheet was measured as follows. That is, after drying this sheet at 100 degrees C for 2 hours, a digital trace moisture measuring device [manufactured by Mitsubishi Kasei Corporation, CA-02] was used.
The measurement was carried out using Type 1 under temperature conditions at which the sheet was sufficiently melted. This temperature condition is, for example, 180 degrees Celsius for a sheet made of polyethylene or polypropylene as a thermoplastic resin, 150 degrees Celsius for a sheet made of ABS resin as a thermoplastic resin, and 230 degrees Celsius for a sheet made of polyamide as a thermoplastic resin. It is C.

Table 1 shows the moisture content of the sheet.

Vacuum forming machine [Plumtsuk FE-36 manufactured by Sanso Kogyo Co., Ltd.
This sheet was vacuum formed into a cylinder with a cross section of 150 mm using a mold, and the maximum drawing depth L and the sharpness of a part of the corner (the part where the circumferential side and the bottom of the cylinder come in contact) were evaluated.

The symbols in Table 1 regarding the sharpness of a part of the corner and their evaluation criteria are shown below.

0...Good mold reproducibility Δ...Slightly rounded and thinner ×...-Torn or rounded.

The surface appearance of the cylinder obtained by vacuum forming was visually evaluated, and the results are shown in Table 1.

The symbols in Table 1 regarding surface appearance and their evaluation criteria are shown below.

0: Smooth and beautiful Δ: Slight foaming or surface roughness X: Severe foaming or surface roughness.

The circumferential side of the cylinder obtained by blow molding was cut out to a width of 25 cm, and a rubber adhesive [manufactured by Sumitomo 3M, EC] was applied to that surface.
-1368] was applied, the cotton cloth was pressed with a 25 ton press at a pressure of 7.5 kg/cm2 for 1 minute, and left for 24 hours. Thereafter, a 180 degree peel test was conducted to measure the peel strength (adhesive strength). The results are shown in Table 1.

The thermoplastic resin, wood flour, and additives used in these Examples and Comparative Examples are as follows.

Polypropylene - Symbol in Table 1: PP, manufactured by Idemitsu Petrochemical Co., Ltd., J-950H1 Water content 0 Polyethylene - Symbol in Table 1: PE, manufactured by Idemitsu Petrochemical Co., Ltd., 210J, moisture content 0 Nylon 6...・Symbols in Table 1: PA, manufactured by Ube Industries, Ltd., 10IIFB, moisture content 0 ABS resin...Symbols in Table 1: ABS, EX-15
1. Moisture content 0 Wood flour...Kist...100779127 items, Moisture content 5.1
5% Talc...Particle size 1oIL, moisture content 0.1% by weight Calcium carbonate・Symbol in Table 1: Charcoal, particle size 5#L
, moisture content 0.15 (hereinafter, margin) Procedural amendment June 22, 1985 2, ゛Patent fi'-JJ official 7
・Mar Indication of the case Patent Application No. 137367, filed in 1980 2 Name of the invention Composite resin sheet 3 Person making the amendment Relationship to the case Patent applicant address 1-277 Kanda Izumi-cho, Chiyoda-ku, Tokyo
Name Calp Industries Co., Ltd. Representative Takeshi Yamato 4 Agent address 2nd floor 6, Karakawa Building, 6-3-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Number of inventions increased by amendment 07 Subject of amendment Detailed explanation of the invention in the specification ” Column 8 Contents of amendment (1) “Vinyl chloride vinyl acetate resin” stated in line 9 of page 4 of the specification is amended to “vinyl chloride vinyl acetate copolymer resin”.

(2) Page 11, line 12 and 12 of the specification
Correct "degree R" written on the first line of the page to "degree C".

(3) "One company" stated in line 1θ of page 17 and line 13 of the same page of the specification is amended to "Co., Ltd."

Claims (2)

[Claims] (1) A composite resin sheet containing 95 to 30% by weight of a thermoplastic resin and 5 to 70% by weight of wood flour, with a moisture content adjusted to 0.5% by weight or less. (2) The composite resin sheet according to claim 1, wherein the composite resin sheet is a composite resin sheet for vacuum forming.