JP2021178498A - Molded body - Google Patents

Abstract

To prevent degradation of natural fibers, and provide a coated molded body with high physical properties and appearance quality, and fabric-like touch and appearance.SOLUTION: The invention is a molded body of a resin composition containing fibers and a thermoplastic resin, the fibers are natural fibers, the thermoplastic resin has a melting point of 120-200°C, and the surface of the molded body is polished to expose the fibers. As an example, a coated molded body 1 having a coating layer 4 of a resin composition containing fibers and thermoplastic resin on the surface of a core material 2 is preferred. The natural fiber is preferably fiber waste, which has an average fiber length of 1-20 mm and is a process waste generated in the manufacturing process of cotton products; the addition ratio is 5-55 wt.%, where the sum of the reinforcing fiber and the thermoplastic resin is taken as the matrix; and the thermoplastic resin is a polyolefin resin.SELECTED DRAWING: Figure 1

Description

The present invention relates to a molded body of a resin composition containing fibers and a thermoplastic resin.

Conventionally, fiber reinforced molded products are well known. Adding fibers to the matrix resin has the advantage of increasing physical properties such as strength. It is also known to reuse fiber scraps as reinforcing fibers. Patent Document 1 describes a mixture of waste plastic made of a specific synthetic resin material, or a plurality of waste plastic groups made of a plurality of different synthetic resin materials, thermosetting resin, wood chips, fiber waste, and the like. It has been proposed to perform plastic molding. Patent Document 2 proposes molding a resin fastener by mixing a flexible thermoplastic resin with synthetic fibers having an average fiber length of 0.1 to 6 mm. Patent Document 3 proposes molding a recycled resin component in which reinforcing fibers such as fiber scraps, wood fibers, glass fibers, and talc are mixed with a waste low-density polyethylene resin. Further, Patent Document 4 proposes to give a woody appearance by extruding and molding a resin composition on a core material and sanding the surface.

Japanese Unexamined Patent Publication No. 2006-305802 Japanese Unexamined Patent Publication No. 2004-346954 Japanese Patent Application Laid-Open No. 2003-261689 Japanese Unexamined Patent Publication No. 2000-141326

However, in the above-mentioned prior art, the fibers are deteriorated by heat in the mixing step and / or the molding step, the physical properties of the molded body are deteriorated, the appearance quality is also deteriorated, and it is difficult to obtain the texture and appearance of the fabric. There was a need for further improvement.

In order to solve the above-mentioned conventional problems, the present invention provides a molded product that prevents deterioration of fibers, has high physical properties and appearance quality, and has a fabric feel and appearance.

The molded product of the present invention is a molded product of a resin composition containing fibers and a thermoplastic resin, wherein the fibers are natural fibers, the thermoplastic resin has a melting point of 120 to 200 ° C., and the molded product has a melting point of 120 to 200 ° C. The surface is polished and the fibers are exposed.

The molded body of the present invention is a molded body of a resin composition containing a fiber and a thermoplastic resin, wherein the fiber is a natural fiber, the thermoplastic resin has a melting point of 120 to 200 ° C., and the molded body of the molded body. Since the surface is polished and the fibers are exposed, deterioration of the fibers can be prevented, the physical properties of the molded body can be maintained high, and a fiber-reinforced molded body having high appearance quality can be provided. In addition, the surface is polished and the fibers are exposed, resulting in a smooth touch and a good appearance. That is, it is possible to provide a molded product having a fabric-like feel and appearance.

1A is a schematic perspective view of a coated molded product according to an embodiment of the present invention, and FIG. 1B is a sectional view thereof. FIG. 2 is a surface enlarged photograph (magnification 40) of the coated molded product of Example 1 of the present invention. FIG. 3 is a surface enlarged photograph (magnification 40) of the coated molded product of Example 2 of the present invention. FIG. 4 is a surface enlarged photograph (magnification 40) of the coated molded product of Example 3 of the present invention. FIG. 5 is a surface enlarged photograph (magnification 40) of the coated molded product of Comparative Example 1.

The molded product of the present invention contains a fiber and a thermoplastic resin, the fiber is a natural fiber, and the thermoplastic resin has a melting point of 120 to 200 ° C. In the present invention, by selecting a natural fiber as the fiber and selecting and combining a thermoplastic resin having a specific melting point as the matrix resin, thermal deterioration of the fiber is suppressed in the mixing step and / or molding step of the fiber and the resin, and the appearance is suppressed. A high-quality molded product can be obtained. Further, the surface of the molded product is polished and the natural fibers are exposed, so that the touch is soft and the appearance is good. In the case of a coated molded product, the thickness of the coating layer before polishing is preferably 1 to 5 mm, more preferably 2 to 3 mm, and the thickness of the coating layer after polishing is preferably 0.5 to 4.5 mm. More preferably, it is 1.5 to 2.5 mm.
The exposure of natural fibers can be confirmed with a microscope for surface observation.

The natural fiber has an average fiber length of preferably 1 to 20 mm, more preferably 2 to 18 mm, still more preferably 3 to 15 mm. Within the above range, it is easy to uniformly mix with the thermoplastic resin of the matrix resin. Natural fibers include plant fiber and animal fiber, plant fiber includes cotton, linen, capoc, palm fiber, sisal fiber, banana fiber, palm fiber, bamboo fiber, and animal fiber includes wool, goat hair, cashmere, mohair, etc. There are angora, alpaca, camel hair, silk, etc., but cotton is preferable from the viewpoint of cost and stable supply.

The addition ratio of the natural fiber is preferably 5 to 55% by weight, more preferably 7 to 50% by weight, still more preferably 20 to 40% by weight when the total of the fiber and the thermoplastic resin is used as a parameter. be. Within the above range, the reinforcing effect of the molded product is higher, and the fibers are easily exposed by polishing.

The natural fiber is preferably cotton. Cotton has a high affinity with thermoplastic resins and has a high reinforcing effect on the molded product. The natural fiber is preferably fiber waste generated in the manufacturing process of cotton products. Examples of the process waste include various process wastes such as fiber waste generated in the raising process, fiber waste generated in the cutting process, and fiber waste generated in the anti-hair process. In addition, fiber scraps obtained by opening and anti-hairing used clothing can also be used. Although such waste has been discarded in the past, collecting and reusing it has an advantage as an effective use of resources. Cotton fiber waste that has undergone the scouring and / or bleaching process has a high degree of whiteness and is preferable. When the whiteness of the fiber waste is high, the color of the base is stable when the fiber waste is colored with a colorant at the time of molding, and the uneven coloring is reduced.

The thermoplastic resin is preferably a polyolefin resin because it has good moldability. Examples of the polyolefin resin include polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA) resin, ionomer resin, ethylene-vinyl alcohol copolymer, and ethylene-vinyl chloride copolymer. Alternatively, a blend of these resins can be used. ABS resin and the like can be used in addition to the polyolefin resin.

It is also possible to construct the molded product with a resin to which fibers are added without using a core material. It is also possible to use the resin as a two-layer extruded product and use a resin in which fibers are added to the covering portion.

The material of the core material is not particularly limited. Materials such as metal, resin, and wood can be selected according to the situation. When strength is required, it is preferable to use a metal as the core material. When the core material is metal, aluminum is preferable. This is because it is excellent in strength, accuracy, and weight. As other metals, iron, stainless steel, copper, various alloys and the like are preferable. Any shape such as a plate, a hollow body, or a pipe can be used as the shape. It can be applied to those used for housing building materials, furniture, shelves, warehouse walls, etc. In the present invention, "made of aluminum" also includes "made of aluminum alloy" in the category, and the same applies to other metals.

It is preferable that an adhesive layer is present between the core material and the coating layer. As the adhesive, for example, a resin containing an epoxy group-containing polyolefin can be used. The thickness of the adhesive layer is preferably 50 to 300 μm, more preferably 100 to 200 μm.

The molded product of the present invention can be produced by the following steps.
(1) A resin composition containing a fiber and a thermoplastic resin is heated to a temperature equal to or higher than the melting point of the thermoplastic resin, melt-kneaded to form a compound, cooled to be granulated or pulverized to obtain pellets.
(2) The pellet is melted and extruded to obtain a molded product having a predetermined shape.
(3) After cooling, the surface of the product is polished to expose the fibers.

The coated molded product of the present invention can be produced by the following steps.
(1) A resin composition containing a fiber and a thermoplastic resin is heated to a temperature equal to or higher than the melting point of the thermoplastic resin, melt-kneaded to form a compound, cooled to be granulated or pulverized to obtain pellets.
(2) The pellet is melted and extruded onto the surface of the core material to form a coating layer.
(3) After cooling, the surface of the coating layer is polished to expose the fibers.

In the kneading process, a kneader such as a kneader is used to mix natural fibers and thermoplastic resin at a temperature higher than the melting of the resin to form a compound (mixture), and this compound is extruded, granulated or crushed into pellets. do. The pellets can be used as a masterbatch and new resin can be added during molding.

Additives such as colorants, various stabilizers, dispersants, compatibilizers and the like may be added in the compounding step and / or the molding step.
Any color can be used as the colorant. Examples of the colorant include pigments, master batches for coloring, dry colors, paste colors, liquid master batches and the like.
Examples of the stabilizer include a heat stabilizer, an antioxidant, a light stabilizer, a surfactant and the like.
Examples of the compatibilizer include unsaturated carboxylic acids. Examples of the unsaturated carboxylic acid include unsaturated monocarboxylic acids and unsaturated dicarboxylic acids, and unsaturated dicarboxylic acids and their anhydrides are particularly preferable, and examples thereof include maleic acid and maleic anhydride.
By changing the color of the colorant, a molded product having an arbitrary color tone can be obtained. The content of the colorant is preferably 3 to 5% by weight based on the polyolefin resin.

In the polishing step, it is preferable to polish the surface of the coating layer in one direction. Polishing is preferably sanding using sandpaper or brushing using a brush. Sandpaper preferably has a count of 24 to 120. Although heat generation may occur during the sanding process, deterioration of the resin can be prevented by having the melting point of the thermoplastic resin at 120 to 200 ° C.

This will be described below with reference to the drawings. In the following, the same reference numerals indicate the same products. FIG. 1 is a schematic perspective view of a coated molded product 1 according to an embodiment of the present invention, and FIG. 1B is a sectional view thereof. In this coated molded body 1, the adhesive layer 3 and the coated layer 4 are integrally extruded on the surface of the core material 2. The core material 2 is hollow aluminum, and the surface of the coating layer 4 is sanded in one direction.

Hereinafter, the present invention will be specifically described with reference to examples. The present invention is not limited to the following examples.

(Example 1)
<Core material>
As the core material 2 shown in FIGS. 1A and 1B, an aluminum hollow material for building materials, an outer diameter of 30 mm, a width of 50 mm, a thickness of 1.2 mm, and a length of 1 m (rectangular cross section, two hollow portions) were used.
<Coating material>
(1) Fiber A cotton fiber waste (raised fiber waste) that has undergone a scouring and bleaching process was used. The average fiber length was 2.0 mm.
(2) Resin A polypropylene resin (PP) having a melting point of 160 ° C. was used. This resin had a melt flow rate (MFR) of 30 g / 10 min at 190 ° C. and 2.16 kgf.
(3) Compound-Pellet PP is weighed at a ratio of 60 parts by weight, fiber waste is 40 parts by weight, and blue colorant is 5.0 parts by weight, melt-kneaded with a kneader heated to a temperature of 190 ° C., extruded, and cooled. Crushed and pelletized. When the total of the fiber waste and the thermoplastic resin was used as a parameter, the fiber waste was 40% by weight.
<Adhesive layer material>
The following adhesive was used as an epoxy group-containing polyolefin resin on the surface of the core material 2.
Bond First (registered trademark) 7B (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate-vinyl acetate (copolymerization ratio (weight ratio) 83: 12: 5), melt flow rate at melting points 95 ° C, 190 ° C, 2.16 kgf) (MFR) 7g / 10min)
<Extrusion coating molding>
An integrally extruded body was manufactured by a coextrusion type integrated extrusion molding machine. The adhesive layer material and the material pellets for the coating layer are extruded from the extruder at the same time, laminated and coated on the aluminum core material in a die, and the adhesive layer and coating are applied to the entire outer surface of the aluminum core material in the circumferential direction. An integrally extruded body having a layer was manufactured. The extrusion conditions and core material conditions are as follows.
・ Extruder: Diameter 40 mm, uniaxial extruder (extrusion temperature approx. 190 ° C)
-The aluminum core material was preheated (about 100 ° C.) immediately before being inserted into the die.
The thickness of the adhesive layer after cooling of the obtained coated molded product was 200 μm, and the thickness of the coated resin was 1.5 mm.
<Polishing>
The surface of the coated molded product was polished with a belt sander. The sandpaper count and polishing method are as follows.
-Sandpaper count: # 40 (sandpaper C40: silicon carbide abrasive)
・ Paper speed: 13m / min
・ Mold feed rate: 8 m / min
The thickness of the coated resin after polishing was 1.0 mm.
As a result of the above, a smooth texture was recognized in both appearance and texture, and a coated molded product having a fabric feeling was obtained. The obtained coated molded article is shown in FIGS. 1A and 1B and FIG. 2 (surface photograph, magnification 40 times).

(Example 2)
At the time of polishing, # 34 (sandpaper 784F: containing 50% ceramic abrasive) was used as sandpaper, and then # 60 (sandpaper C60: silicon carbide abrasive) was used for polishing. The points other than the above were carried out in the same manner as in Example 1. The obtained coated molded product is shown in FIG. 3 (surface photograph, magnification 40 times).

(Example 3)
At the time of polishing, # 34 (sandpaper 784F: containing 50% ceramic abrasive) was used as sandpaper, and then # 60 (sandpaper C60: silicon carbide abrasive) was used for polishing twice. The points other than the above were carried out in the same manner as in Example 1. The obtained coated molded product is shown in FIG. 4 (surface photograph, magnification 40 times).

(Comparative Example 1)
The procedure was carried out in the same manner as in Example 2 except that wood powder was used instead of fiber waste. The obtained coated molded product is shown in FIG. 5 (surface photograph, magnification 40 times).

The fabric feeling was evaluated from the appearance and smoothness of the touch of Examples 1 to 3 and Comparative Example 1, and the results are shown in Table 1.
・ Appearance (smoothness)
A: Good B: Intermediate C: Bad / feel (smoothness)
A: Smooth feeling B: Middle C: Rough feeling / Fabric feeling A: Good B: Middle C: Bad

In Examples 1 to 3, the smoothness of appearance and the feel were above a certain level, and a fabric feeling was obtained. In Comparative Example 1, a fabric feeling was not obtained.

The coated molded article of the present invention is useful for building materials, furniture, shelves, warehouse walls, vehicle interior walls, and the like.

1 Coated molded body 2 Core material 3 Adhesive layer 4 Coated layer

Claims (10)

A molded product of a resin composition containing fibers and a thermoplastic resin.
The fiber is a natural fiber and
The thermoplastic resin has a melting point of 120 to 200 ° C.
A molded product characterized in that the surface of the molded product is polished and the fibers are exposed. The molded product according to claim 1, wherein the molded product is a coating layer coated on the surface of the core material. The molded product according to claim 1 or 2, wherein the natural fiber has an average fiber length of 1 to 20 mm. The molded product according to any one of claims 1 to 3, wherein the natural fiber addition ratio is 5 to 55% by weight when the total of the fibers and the thermoplastic resin is used as a parameter. The molded product according to any one of claims 1 to 4, wherein the natural fiber is cotton fiber waste. The molded product according to any one of claims 1 to 5, wherein the natural fiber is a process waste generated in the manufacturing process of a cotton product. The molded product according to any one of claims 1 to 6, wherein the thermoplastic resin is a polyolefin resin. The molded product according to any one of claims 2 to 7, wherein the surface of the coating layer is polished in one direction. The molded product according to any one of claims 2 to 8, wherein an adhesive layer is present between the core material and the coating layer. The molded product according to any one of claims 2 to 9, wherein the core material is made of aluminum.

Images