JPH0267326A - Fiber-reinforced thermoplastic resin composition with excellent surface flatness - Google Patents

Abstract

PURPOSE:To obtain the title compsn. useful for the products to be used for an automotive outer panel, outer members of industrial and domestic machinery, etc., by incorporating a filler in a compsn. comprising a thermoplastic resin and reinforcing fiber under a specified condition. CONSTITUTION:1-50wt.% filler (e.g. kaoline clay, carbonaceous whisker, etc.,) is compounded with 99-50wt.% compsn. comprising 40-80wt.% thermoplastic resin (e.g. PP) and 60-20wt.% reinforcing fiber with a fiber diameter of 3-20mum and a fiber length of 1-50mm (e.g. glass fiber) at such a ratio that when the aspect ratio of the filler is smaller than 3, the diameter of the inscribed sphere is selected to be at most one fourth of said reinforcing fiber and when said aspect ratio is 3 or larger, the fiber diameter is selected to be at most one fourth of said reinforcing fiber and the linear expansion coefficient of the binary compsn. comprising said filler and said thermoplastic resin is to be at most 90% of that of said thermoplastic resin.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fiber-reinforced thermoplastic resin composition, and more specifically, a fiber-reinforced thermoplastic resin composition that has excellent mechanical properties and sheet surface smoothness. This invention relates to a resin composition.

[Prior art]

Examples of fiber-reinforced thermoplastic resin compositions consisting of a thermoplastic resin and reinforcing fibers include FRTP in which chopped glass fibers are dispersed in a matrix resin, or fiber-reinforced thermoplastic resin compositions in which a swirl mat made of long glass fibers is used as a reinforcing layer. Resin sheets are well known.

[Problem 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 mats are 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 disadvantages of using this swirl mat, JP-A-60-1
No. 58228 discloses that "2Of! reinforcing fibers having a high elastic modulus and mostly having a length of 7 mm to 50 mm and a diameter of 13 μm or less and 40% to 80% of reinforcing fibers by weight. There is a fiber-reinforced sheet made of a thermoplastic material of approximately 50%, but the surface smoothness is not satisfactory.

[Means to solve the problem]

In view of these circumstances, the present inventors have conducted intensive studies and found that by adding a specific filler to the matrix resin, it is possible to provide a fiber-reinforced thermoplastic resin composition with excellent surface smoothness of molded products. They discovered this and completed the present invention.

That is, the present invention comprises (A) a thermoplastic resin of 40 to 80% by weight and a fiber diameter of 3 to 80% by weight;
A composition consisting of 60 to 20% by weight of reinforcing fibers of 20 μm/fiber length 1 to 50 aa, 99 to 50% by weight, and (B) a filler, 1 to 50% by weight, and (C) the aspect ratio of the filler is When the aspect ratio is less than 3, the diameter of the interpolated sphere, and when the aspect ratio is 3 or more, the fiber diameter is less than or equal to the reinforcing fiber diameter, and (D) the filler and the heat The filler is contained in a composition ratio such that the coefficient of linear expansion of the component composition with the plastic resin is 90% or less of the coefficient of linear expansion of the thermoplastic resin, and has excellent surface smoothness. A fiber reinforced thermoplastic resin composition is provided.

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, and nylon. 6. Poamide resins such as nylon 66 and nylon 46, polyether resins such as polyphenylene ether and modified polyphenylene ether, polyoxymethylene resins, polycarbonate resins, polyarylates, polyphenylene sulfides, polysulfones, polyether sulfones, polyether ether ketones , super heat-resistant wood such as polyetherimide or polycarbonate/
Examples include blend polymers such as ABS, polyphenylene ether/polyamide, polycarbonate/polybutylene terephthalate, and polyphenylene ether/polybutylene terephthalate.

The reinforcing fibers used in the present invention may be of any type 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. , stainless steel, metal fibers such as brass, 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 Examples include organic fibers such as aramid fibers, polyphenylene benzothiazole fibers, polyacrylonitrile fibers, and cellulose fibers.

The reinforcing fibers have a diameter of 3 to 50 .mu.m. If the diameter is less than 3 .mu.m, it is difficult to disperse the reinforcing fibers, which is not preferable. Further, if the reinforcing fiber exceeds 20 μm, it is undesirable because it tends to break during dispersion.The length of the reinforcing fiber is 1 to 50, preferably 1 to 25+1111. When most of the reinforcing fibers are less than fin, 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, if it is spherical or has a shape close to a sphere (when the aspect ratio is less than 3), the diameter of the inserted sphere is reinforced. The fiber diameter is approximately X or less. Further, if the shape is fibrous (aspect ratio is 3 or more), the fiber diameter may be about X or less of the reinforcing fiber diameter. In the above-mentioned filler having a shape with a distribution of diameters, 60% by weight or more, preferably 70% by weight
It is sufficient if the above is equal to or less than X of the reinforcing fiber diameter.

The aspect ratio is defined as the ratio of the long axis to the short axis when the shape is spherical or nearly spherical, and the ratio of the fiber length to the fiber diameter when the shape is fibrous.

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 heating rate is 10
℃/llll1n.

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 balloons. , quartz balloon, graphite, boron, alumina, silicon carbide, boron carbide, boria, boron nitride, silica, beryllium, quartz, silicon nitride, beryllium oxide, inorganic powders such as aluminum nitride, asbestos, potassium titanate, carbon, graphite, Inorganic whiskers such as boron, alumina, silicon carbide, boron carbide, boria, boron nitride, silica, beryllium, quartz, silicon nitride, microcellulose, thermosetting resin powder, aramid pulp, matrix of fiber reinforced thermoplastic resin composition Ultrafine fibers of thermoplastic resin having a melting point higher than the melting point of the resin, such as ultrafine polyethylene terephthalate fibers,
Or powder etc. are mentioned. Two or more of these fillers can also be used in combination.

The amount of the 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 coefficient of the thermoplastic resin The preferred amount varies depending on the combination of matrix and reinforcing fibers, as long as the amount is 90% or less of the fiber-reinforced thermoplastic resin composition. The total weight with fibers is 99 to 50% by weight, the filler is 1% to 50% by weight,
Preferably it is in the range of 5% to 30% by weight.

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 fiber, and filler are tri-blended and kneaded using an extruder, roll, Banbury mixer, or the like. In addition, as described in JP-A-57-28135, JP-A-58-592.24, etc., fiber reinforced There is a method in which a thermoplastic resin composition is produced, and the resin is melted and integrated with reinforcing fibers and a filler using an in-line or online hot press such as a belt press.

The composition of the present invention includes flame retardants, heat stabilizers, ultraviolet inhibitors,
Various stabilizers such as colorants may be added to the extent that the mechanical properties of the composition are not impaired.

〔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 45 parts of polypropylene (melt flow index Ml = 4) powder,
30 parts of glass fiber with a diameter of 10 μm and a length of 6 mm and 25 parts of potassium titanate whiskers of steel with a diameter of 0.2-0.5 μm
A sheet-like composition was obtained by a papermaking method. This is 200
The material was melted and solidified by compression molding at 100 kg/cii at a temperature of 100 kg/cii, and its physical properties were measured.

The properties are shown in the table. A composition of polypropylene resin and potassium titanate whiskers was produced by a papermaking method and the coefficient of linear expansion was measured to be 40 x 10-hcm/cm・℃.
and the coefficient of linear expansion of polypropylene is 230 x 10
−'cm/cm·°C was 17%. Surface smoothness was evaluated by image clarity. The larger the value, the better the surface smoothness.

Comparative Example 1 A melt-solidified sheet consisting of 60 parts of polypropylene powder and 40 parts of glass fiber (diameter 10 μs+, length 6 mm) was produced in the same manner as in Example 1. The characteristics are shown in the table.

Example 2 49 parts of polyethylene terephthalate powder, diameter 10 μm
, 21 parts of glass fiber of length 13ffi11, diameter 0.
A mat was prepared from 30 parts of carbonaceous whiskers of 0.05 to 0.5 μm by a papermaking method, and then heated at 300'C and 100kg.
A melt-solidified sheet was formed by compression molding under a pressure of /cd. The characteristics are shown in the table. The linear expansion coefficient of the composition of polyethylene terephthalate and carbonaceous whiskers is 45 x 10
- 'cm/cm・''C, and the linear expansion coefficient of polyethylene terephthalate resin is 200X10-hcm/cm・℃
However, it was 3%.

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 10 μm
, 36 parts of glass fiber with a length of 13 mm and an average particle size of 1
A sheet was melted and solidified using the same method as in Example 1 using 10 parts of aluminum hydroxide powder having a diameter of μm. The characteristics are shown in the table. The linear expansion coefficient of the composition of polypropylene and aluminum hydroxide is 160 x 10-'cm/cm・''C, and the linear expansion coefficient of the polypropylene resin is 230 x 10-'
'C1l/e1m 70% of 'C.

Comparative Example 3 Aluminum hydroxide powder with an average particle size of 3.5 μm
A melt-solidified sheet was produced with the same composition as in Example 3 except that the powder was used. The characteristics are shown in the table.

Example 4 45 parts of polypropylene (MI=4) powder, diameter 6 μm,
A melt-solidified sheet was prepared in the same manner as in Example 1 using 50 parts of glass fiber having a length of 13III full and 5 parts of hard clay type kaolin clay having 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 x 1
0-'cm/cu+ ・"C, and the linear expansion coefficient of polypropylene resin is 230 x 10-6cm/cm・"C 8
It was 5%.

Comparative Example 4 A melt-solidified sheet was produced using the composition of Example 2, which did not contain hard clay-type kaolin clay. The characteristics are shown in the table.

Blank below [Effects of the Invention] According to the present invention, the filler has a specific size and the linear expansion coefficient of the composition of the filler and the thermoplastic resin is 90% or less of the linear expansion coefficient of the thermoplastic resin. By adding a filler in such a manner that 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 external parts 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.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] (A) Thermoplastic resin 40-80% by weight and fiber diameter 3-80% by weight
A composition consisting of 60 to 20% by weight of reinforcing fibers of 20 μm and a fiber length of 1 to 50 mm, 99 to 50% by weight, and (B) a filler, 1 to 50% by weight, and (C) an aspect ratio of the filler. is less than 3, the diameter of the interpolated sphere, and when the aspect ratio is 3 or more, the fiber diameter is less than or equal to the reinforcing fiber diameter, and (D) the filler and the Excellent surface smoothness characterized by containing the filler in a composition ratio such that the coefficient of linear expansion of the two-component composition with a thermoplastic resin is 90% or less of the coefficient of linear expansion of the thermoplastic resin. Fiber-reinforced thermoplastic resin composition