JPH0411579B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a fiber-reinforced thermoplastic resin composition, and more particularly, to a fiber-reinforced thermoplastic resin composition that has excellent mechanical properties and sheet surface smoothness. be. [Prior art] As a fiber-reinforced thermoplastic resin composition consisting of a thermoplastic resin and reinforcing fibers, ERTP, which has chopped glass fibers dispersed in a matrix resin, or fiber-reinforced thermoplastic resin composition, which has a swirl mat made of long glass fibers as a reinforcing layer, can be used. Plastic resin sheets are well known. [Problems to be Solved by the Invention] However, since these fiber-reinforced thermoplastic resin compositions and sheets use glass fibers, the surface smoothness of the molded products is poor. In particular, when swirl mat is used as reinforcing fibers, the fibers protrude from the surface of the molten resin during molding, resulting in extremely poor surface smoothness. To overcome the drawbacks of using swirl mats, Japanese Patent Application Laid-Open No. 158228/1987 discloses a method of using swirl mats that are described in Japanese Patent Application Laid-Open No. 158228/1982. wt% to 60wt% reinforcing fibers and 40wt%
There is a fiber-reinforced sheet consisting of 80% by weight of a thermoplastic material, but the surface smoothness is still unsatisfactory. [Means for Solving the Problems] In view of the above circumstances, the inventors of the present invention have made extensive studies and found that the surface smoothness of the molded product can be improved by adding a specific filler to the matrix resin. The present invention was completed by discovering that it is possible to provide a fiber-reinforced thermoplastic resin composition. That is, the present invention comprises A thermoplastic resin of 40 to 80% by weight and a fiber diameter of 3 to 80% by weight.
20μm, fiber length 1-50mm reinforcing fibers 60-20% by weight
A composition consisting of 99-50% by weight and filler B, 1-50% by weight
C. When the aspect ratio of the filler is less than 3, the diameter of the interpolated sphere is 1% of the reinforcing fiber diameter, and when the aspect ratio is 3 or more, the fiber diameter is 1 of the reinforcing fiber diameter. /4 or less, and D the linear expansion coefficient of the two-component composition of the filler and the thermoplastic resin is 90% of the linear expansion coefficient of the thermoplastic resin.
The present invention provides a fiber-reinforced thermoplastic resin composition with excellent surface smoothness, which contains the filler in the following composition ratio. Thermoplastic resins used in the present invention include polyolefin resins such as polyethylene and polypropylene, polystyrene, rubber-reinforced polystyrene, acrylonitrile-styrene copolymers, styrenic resins such as ABS resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate,
Poamide resins such as nylon 6, nylon 66, and nylon 46, polyether resins such as polyphenylene ether and modified polyphenylene ether, polyoxymethylene resins, polycarbonate resins, polyarylates, polyphenylene sulfide, polysulfone, Examples include super heat-resistant resins such as polyether sulfone, polyether ether ketone, and polyetherimide, and blend polymers such as polycarbonate/ABS, polyphenylene ether/polyamide, polycarbonate/polybutylene terephthalate, and polyphenylene ether/polybutylene terephthalate. It will be done. The reinforcing fibers used in the present invention may be anything as long as they have a tensile modulus higher than the tensile modulus of the thermoplastic resin used in the present invention, such as inorganic fibers such as glass fibers, carbon fibers, ceramic fibers, and mineral fibers. , metal fibers such as stainless steel and brass,
Aramid fibers such as ultra-high molecular weight polyethylene fibers, polyoxymethylene fibers, polyvinyl alcohol fibers, liquid crystalline aromatic polyester fibers, polyethylene terephthalate fibers, poly-p-phenylene terephthalate fibers, poly-m-phenylene isophthalamide fibers, polyphenylene fibers, etc. Examples include organic fibers such as nylenebenzothiazole fiber, polyacrylonitrile fiber, and cellulose fiber. The diameter of the reinforcing fibers is 3 to 50 μm, and if it is less than 3 μm, it is difficult to disperse and is not preferred. Moreover, if it exceeds 20 μm, it is undesirable because it tends to break during dispersion.
The length of the reinforcing fibers is 1 to 50 mm, preferably 1 to 25 mm. When most of the reinforcing fibers are less than 1 mm, no reinforcing effect of the composition is observed. Further, if the length exceeds 50 mm, uniform dispersion is difficult. The amount of reinforcing fibers is 20-60% by weight, preferably 30-50% by weight. If it is less than 20% by weight, the reinforcing effect will not be very noticeable, and if it exceeds 60% by weight, the composition will become brittle, which is not preferable. The filler used in the present invention may have any shape. That is, when the shape is spherical or close to a sphere (when the aspect ratio is less than 3), the diameter of the interpolated sphere is about 1/4 or less of the reinforcing fiber. Also, the shape is fibrous (aspect ratio is 3 or more)
If so, the fiber diameter may be approximately 1/4 or less of the reinforcing fiber diameter. In the above-mentioned filler having a shape with a distribution of diameters, it is sufficient that 60% by weight or more, preferably 70% by weight or more is 1/4 or less of the reinforcing fiber diameter. The aspect ratio is defined as the ratio of the major axis to the minor axis in the case of a spherical or nearly spherical shape, and the ratio of the fiber length to the fiber diameter in the case of a fibrous shape. Further, when the coefficient of linear expansion of the composition of the filler and the thermoplastic resin is 90% or less of the coefficient of linear expansion of the thermoplastic resin, the composition has excellent surface smoothness. The coefficient of linear expansion is a value measured in the range from 30°C to a temperature 30°C lower than the melting point or glass transition temperature of the thermoplastic resin. The temperature increase is 10°C/min. Examples of fillers include calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum silicate, talc, wollastonite, silicic acid,
Calcium silicate, aluminum silicate, mica, glass balloon, quartz balloon, graphite, boron,
Inorganic powders such as alumina, silicon carbide, boron carbide, boria, boron nitride, silica, beryllium, quartz, silicon nitride, beryllium oxide, aluminum nitride, asbestos, potassium titanate, carbon, graphite,
Boron, alumina, silicon carbide, boron carbide, boria, boron nitride, silica, beryllium, quartz,
Inorganic whiskers such as silicon nitride, microcellulose, thermosetting resin powder, aramid pulp, ultrafine fibers of thermoplastic resin having a melting point higher than the melting point of the matrix resin of fiber-reinforced thermoplastic resin compositions, such as ultrafine polyethylene terephthalate fibers. etc., or powder. Two or more of these fillers can also be used in combination. The amount of filler added should be determined so that the coefficient of linear expansion of the composition of the filler and the thermoplastic resin serving as a matrix is such that the expansion of the thermoplastic resin 90% of rate
The following blending amount is sufficient, so the preferred blending amount changes depending on the combination of matrix and reinforcing fibers, but in general, the total weight of the thermoplastic resin and reinforcing fibers that make up the fiber-reinforced thermoplastic resin composition. but
99-50% by weight, with fillers ranging from 1% to 50%, preferably 5% to 30%. Various known techniques can be used to manufacture the fiber-reinforced thermoplastic resin composition of the present invention. For example, there is a method in which a thermoplastic resin, reinforcing fibers, and filler are dry blended and kneaded using an extruder, roll, Banbury mixer, or the like. Also, Tokukai Akira
As described in Japanese Patent Publication No. 57-28135, Japanese Patent Application Laid-Open No. 58-59224, etc., a fiber-reinforced thermoplastic resin composition is prepared from a powdered thermoplastic resin, reinforcing fibers, and a filler by a paper-making method. There is a method in which the resin is melted and the reinforcing fibers and filler are integrated using a hot press such as a belt press in-line or online. Various stabilizers such as flame retardants, heat stabilizers, ultraviolet inhibitors, colorants, etc. may be added to the composition of the present invention to the extent that they do not impair the mechanical properties of the composition. [Example] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. In the examples, parts indicate parts by weight. Example 1 Polypropylene (melt flow index MI=4) powder
45 parts, 30 parts of glass fibers with a diameter of 10 μm and a length of 6 mm and 25 parts of potassium titanate whiskers with a diameter of 0.2-0.5 μm.
A sheet-like composition was obtained by a papermaking method. this
The material was melted and solidified by compression molding at 200° C. and a pressure of 100 kg/cm ² and its physical properties were measured. The characteristics are shown in the table. In addition, as a result of manufacturing a composition of polypropylene resin and potassium titanate whiskers using a papermaking method and measuring the linear expansion coefficient, it was 40 × 10 ^-6 cm /
cm・℃, and the coefficient of linear expansion of polypropylene is 230
It was 17% of ×10 ^-6 cm/cm・℃. Surface smoothness was evaluated by image clarity. The larger the value, the better the surface smoothness. Comparative Example 1 Polypropylene powder 60% was prepared in the same manner as in Example 1.
A melt-solidified sheet consisting of 40 parts of glass fiber (10 μm in diameter, 6 mm in length) was prepared. The characteristics are shown in the table. Example 2 49 parts of polyethylene terephthalate powder, diameter
21 parts of glass fiber of 10μm, length 13mm, diameter 0.05
A mat was prepared from 30 parts of carbonaceous whiskers of ~0.5 μm by a papermaking method, and then melted and solidified into a sheet by compression molding at 300° C. and a pressure of 100 Kg/cm ² . The characteristics are shown in the table. The linear expansion coefficient of the composition of polyethylene terephthalate and carbonaceous whiskers is 45×10 ^-6
cm/cm·°C, which was 23% of the linear expansion coefficient of polyethylene terephthalate resin, 200×10 ^-6 cm/cm·°C. Comparative Example 2 A melt-solidified sheet was produced using the composition of Example 2, which did not contain carbonaceous whiskers. The characteristics are shown in the table. Example 3 54 parts of polypropylene (MI=4) powder, diameter
A melt-solidified sheet was prepared in the same manner as in Example 1 using 36 parts of glass fiber having a diameter of 10 μm and a length of 13 mm and 10 parts of aluminum hydroxide powder having an average particle diameter of 1 μm. The characteristics are shown in the table. The coefficient of linear expansion of the composition of polypropylene and aluminum hydroxide is 160×10 ^-6
cm/cm·°C, which was 70% of the linear expansion coefficient of polypropylene resin, 230×10 ⁻⁶ cm/cm·°C. Comparative Example 3 As aluminum hydroxide powder, the average particle size is
A melt-solidified sheet was produced with the same composition as in Example 3 except that 3.5 μm powder was used. The characteristics are shown in the table. Example 4 45 parts of polypropylene (MI=4) powder, diameter
A melt-solidified sheet was prepared in the same manner as in Example 1 using 50 parts of glass fibers of 6 μm and 13 mm in length and 5 parts of hard clay type kaolin clay with an average particle diameter of 0.4 μm. The characteristics are shown in the table. The linear expansion coefficient of the composition of polypropylene and hard clay-type kaolin clay is 195×10 ^-6 cm/cm・℃, which is 85% of the linear expansion coefficient of polypropylene resin, 230×10 ⁻⁶ cm/cm・℃. Ta. Comparative Example 4 A melt-solidified sheet was produced with the composition of Example 2, which did not contain hard clay-type kaolin clay. The characteristics are shown in the table.

〔Effect of the invention〕

According to the present invention, the filler is added so that the filler has a specific size and the coefficient of linear expansion of the composition of the filler and the thermoplastic resin is 90% or less of the coefficient of linear expansion of the thermoplastic resin. By doing so, a composition with excellent surface smoothness can be obtained very easily. Therefore, it is useful for products in fields where surface smoothness is desired, such as exterior panels for automobiles, and parts exposed to the outside of industrial and consumer equipment. In addition, various post-processing to improve surface smoothness, such as coating, lamination of films, and raising the temperature of the molding die, are not required, resulting in lower costs.

Claims (1)

[Claims] 1 A thermoplastic resin 40-80% by weight and fiber diameter 3
Composition consisting of 60-20% by weight of reinforcing fibers of ~20 μm and fiber length of 1-50 mm, 99-50% by weight and filler B, 1
C. When the aspect ratio of the filler is less than 3, the diameter of the inserted sphere is equal to the reinforcing fiber diameter, and when the aspect ratio is 3 or more, the fiber diameter is equal to the reinforcing fiber diameter. D is 1/4 or less, and the coefficient of linear expansion of the two-component composition of the filler and the thermoplastic resin is 90% of the coefficient of linear expansion of the thermoplastic resin.
A fiber-reinforced thermoplastic resin composition with excellent surface smoothness, characterized by containing the filler in the following composition ratio: