JPH0411576B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a fiber-reinforced thermoplastic resin sheet, and more particularly to a fiber-reinforced thermoplastic resin sheet that has excellent mechanical properties and sheet surface smoothness. [Prior Art] Various studies have been made on fiber-reinforced thermoplastic resin sheets made of thermoplastic resin and reinforcing fibers. For example, there may be mentioned a fiber-reinforced thermoplastic resin sheet having a swirl mat made of long glass fibers as a reinforcing layer. [Problems to be Solved by the Invention] However, since this reinforcing sheet uses long glass fibers, the surface smoothness of the molded product is extremely poor, and in addition, the long glass fibers are oriented in undefined directions. Because it extends in a spiral shape, the glass fiber moves slowly during stamping and cannot follow the flow of the thermoplastic resin, making it difficult to obtain deep-drawn products with uniform fiber distribution. It is. To overcome these drawbacks, JP-A-60
-Described in Publication No. 158228, ``It has a high elastic modulus, and most of it has a length of 7 mm to 50 mm and a length of 13 μm.
There is a "fiber reinforced sheet" consisting of 20% to 60% by weight of reinforcing fibers and 40% to 80% by weight of a thermoplastic material having the following diameters, but although this sheet also has improved deep drawability, The surface smoothness of the sheet is still insufficient and unsatisfactory. [Means for Solving the Problems] In view of the above circumstances, the inventors of the present invention have made intensive studies, focused on the dimensions of the reinforcing fibers, and determined that the main composition of the reinforcing fibers is short fibers. The present invention was completed based on the discovery that a fiber-reinforced thermoplastic resin sheet with excellent sheet surface smoothness and deep drawability can be provided by using a mixture of a specific amount of long fibers. That is, the present invention provides (A) a thermoplastic resin and (B) a fiber diameter.
60% to 95% by weight of reinforcing fibers of 3 μm to 13 μm and fiber length of 3 mm to 7 mm and fiber diameter of 6 μm to 20 μm and fiber length of 7
It consists of mixed fibers consisting of 40% to 5% by weight of reinforcing fibers of mm to 50mm, and (A) is 40% to 80% by weight.
The present invention provides a fiber-reinforced resin sheet comprising a mixture in which (B) is 60% to 20% by weight. Thermoplastic resins used in the present invention include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins such as nylon 6 and nylon 66, polysulfone, polyether sulfone, polyether ether ketone, polyester resin, etc. In addition to so-called super engineering plastic resins such as etherimide, any thermoplastic resin that can be formed into a sheet by some means may be used. Furthermore, the shape of the resin used when producing a fiber-reinforced thermoplastic resin sheet by a papermaking method is preferably powder-like and/or fibrous-like. In the case of powdered thermoplastic resin, the particle size is 0.01 mm to 2 mm as the average diameter of the inserted sphere, and the shape may be any shape such as fibrous, spherical, cylindrical, dice-like, etc. It also includes pulp-like materials whose main fibers are 3 mm or less in length. In addition, in the case of fibrous thermoplastic resin, the average diameter of the fibers is 3 μm to 500 μm, and the cross-sectional shape may be any shape such as circular or polygonal, as long as there is no problem in paper making. The length is 3 mm to 25 mm. The diameter of the interpolated sphere here is expressed by converting an arbitrary shape into a sphere of the same volume and using the diameter at that time. To calculate the average diameter of the interpolation sphere, measure the particle size distribution by sieving, take the arithmetic average value of the openings of adjacent sieves, take it as the representative particle size of particles in this category, and calculate the weight. Based on Rosin−Rammler
Find the particle size at 50% on the sieve using the formula, collect 10 particles corresponding to this from the sieved sample, convert each to the diameter of the interpolation sphere, and calculate the arithmetic mean value. The average diameter of the inserted bulb. The reinforcing fibers used in the present invention may be of any type as long as they have a higher modulus of elasticity than the thermoplastic resin used for the fiber-reinforced thermoplastic resin sheet, such as glass fibers, carbon fibers, ceramic fibers, stainless steel, etc. Examples include metal fibers, mineral fibers, aramid fibers, etc. The dimensions of the reinforcing fibers are as follows: Short fibers, which are the main components of the reinforcing fibers, have a fiber diameter of 3 μm to 13 μm and fiber lengths of 3 mm to 7 mm, and long fibers, which are secondary components, have a fiber diameter of 6 μm to 20 μm. Fiber length 7mm
~50mm. The short fibers, which are the main component of the reinforcing fibers, contribute to improving the surface smoothness of the sheet, and the long fibers, which are the minor component of the reinforcing fibers, contribute to improving the mechanical properties of the sheet. Increasing the amount of long fiber reinforcing fibers mixed improves the mechanical properties of the sheet, but inversely proportional to this, the deep drawability of the sheet deteriorates. Therefore, the important factors that influence the mechanical properties of the sheet, the surface smoothness of the sheet, and the deep drawability of the sheet are the short fibers, which are the main components of the reinforcing fibers, and the secondary components of the reinforcing fibers. This is the mixing ratio of certain long fibers. The mixing ratio of short fibers, which are the main components of reinforcing fibers, is in the range of 60% to 95% by weight, and the mixing ratio of long fibers, which are the secondary components of reinforcing fibers, is in the range of 40% to 5% by weight. In this case, it is possible to obtain a fiber-reinforced thermoplastic resin sheet that has good mechanical properties and is excellent in surface smoothness and deep drawability. The blending ratio of the thermoplastic resin constituting the fiber-reinforced thermoplastic resin sheet is in the range of 40% to 80% by weight, preferably in the range of 50% to 70% by weight. When the blending ratio of thermoplastic resin is less than 40% by weight, it is difficult to sheet the fiber-reinforced thermoplastic resin sheet, and when the blending ratio exceeds 80% by weight, the effect of fiber reinforcement of the fiber-reinforced thermoplastic resin sheet is impaired. However, the mechanical properties deteriorate. At least one type of inorganic or/and organic filler is used for the purpose of imparting opacity to the fiber-reinforced thermoplastic resin sheet, reducing the heat shrinkage rate, adjusting the fluidity of the sheet during molding, adjusting the coefficient of linear expansion, etc. can be added. Examples of the inorganic filler to be added include silica compounds, calcium carbonate, wlastonite, mica, and microglass. Examples of the organic filler include microcellulose, thermosetting resin powder, and thermoplastic resin powder having a melting point higher than that of the thermoplastic resin constituting the fiber-reinforced thermoplastic resin sheet. The amount of filler added may vary depending on the situation, as long as it does not impede the mechanical properties or other characteristics of the fiber-reinforced thermoplastic resin sheet, and the amount of filler added may vary depending on the total weight of the thermoplastic resin and reinforcing fibers that make up the fiber-reinforced thermoplastic resin sheet. in the range of 1% to 50% by weight, preferably 5% by weight.
It is preferable to determine it in the range of 30% by weight. The fiber-reinforced thermoplastic resin sheet of the present invention is
anionic or cationic polymeric crosslinking agent,
Wet paper strength agents such as polyethyleneimine, dialdehyde starch, methylolated polyamide, CMC,
By adding dry paper strength enhancers such as PVA, modified starch, etc., as appropriate by internal addition method or external addition method,
The wet strength and/or dry strength of the sheet may be imparted. Furthermore, instead of the above-mentioned paper strength enhancer, cellulose pulp, aramid pulp, vertical fibers, etc. may be added. Various known techniques can be used to manufacture the fiber-reinforced thermoplastic resin sheet of the present invention. For example, from thermoplastic resin fibers and reinforcing fibers,
A dry nonwoven fabric manufacturing method includes a method in which an original fabric of a fiber-reinforced thermoplastic resin sheet is manufactured, and then the resin is melted using a hot press and bonded and integrated with reinforcing fibers. Also, JP-A-57-28135, JP-A-58-59224
As described in the above publication, a raw material of a fiber-reinforced thermoplastic resin sheet is manufactured from a powdered thermoplastic resin and reinforcing fibers by a paper-making method, and then hot-pressed using a belt press or the like in-line or offline. There is a method of melting the resin and bonding and integrating it with the reinforcing fibers. Regardless of which manufacturing method is adopted, for example, in order to create a sheet with a thickness of 0.5 mm or more, a plurality of original sheets are laminated and passed through a hot press. When laminating sheets, it is possible to change the blending ratio of reinforcing fibers in the skin layer and core layer, or to use different thermoplastic resins in the skin layer and core layer. [Example] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 (a) Polypropylene with an MFI of 14 (average diameter of interpolated spheres 0.3 mm), 3.0% by weight slurry water made by adding 0.2% by weight of an amine type nonionic surfactant to the polypropylene, ( b) 70% by weight glass fiber with a fiber diameter of 10 μm and a fiber length of 6 mm and a fiber diameter of 10 μm,
1.0% by weight of mixed reinforcing fiber slurry water made by adding 0.15% by weight of a polyethylene glycol ester type dispersant to this mixed reinforcing fiber. After each preparation, (a):(b) are mixed in a ratio of 1:3 to create a 1.5% by weight slurry water consisting of 50% by weight of polypropylene and 50% by weight of mixed reinforcing fibers, and then this slurry After diluting the slurry with water to give a slurry concentration of 0.4% by weight, a web with a basis weight of 260 g was produced using a hand sheet machine. Ten sheets of this web were laminated and dehydrated using a press, then dried at 120℃ for 1 hour, heated for 16 minutes using a sheet forming press at a temperature of 190℃ and a pressure of 10Kg/ ^cm2 , and then temperature 25℃, pressure 15
It was cooled for 20 minutes under conditions of Kg/cm ² to form a fiber-reinforced thermoplastic resin sheet with a thickness of 2 mm. The properties of this sheet are shown in Table 1.

【table】

[Table] Comparative Example 1 (a) 3.0% by weight slurry water made by adding 0.2% by weight of an amine-type ionic surfactant to polypropylene with an MFI of 14 (average diameter of interpolated spheres: 0.3 mm) and this polypropylene. (b) A glass fiber with a fiber diameter of 10 μm and a fiber length of 13 mm, and a polyethylene glycol ester type dispersant applied to this glass fiber.
After preparing glass fiber slurry water of 0.2% by weight and 0.3% by weight with addition of 10% by weight of a sodium polyphosphate type thickener, (a):(b) were mixed in 1:1. Create a slurry water of 50% polypropylene and 50% glass fiber by mixing in the proportion of 10% by weight,
Next, this slurry water was diluted with water to make the slurry concentration 0.3% by weight, and then a web having a basis weight of 260 g was produced using a hand sheet machine. thickness 2
A fiber-reinforced thermoplastic resin sheet having a diameter of 1 mm was prepared in exactly the same manner as in Example 1. The properties of this sheet are shown in Table 2.

[Table] As a guide, a value of 10 or more is considered good for image clarity, and a value of 5 or less is considered good for deep drawability. Mechanical properties such as tensile breaking strength and Izod impact strength are relative, and their superiority or inferiority is determined by the type and blending ratio of the thermoplastic resin and mixed reinforcing fibers that make up the fiber-reinforced thermoplastic resin sheet. It is determined by In the case of Comparative Example 1, the mechanical properties are somewhat better than in Example 1, but the image clarity and deep drawability are very poor. Comparative example 2 (a) Polypropylene of FI14 (average diameter of interpolated sphere
0.3mm), 3.0% by weight slurry water made by adding 0.2% by weight of an amine type nonionic surfactant to this polypropylene, (b) glass fibers with a fiber diameter of 10μm and a fiber length of 6mm, and this glass. Applying polyethylene glycol ester type dispersant to fibers
After preparing 1.0% by weight glass fiber slurry water by adding 0.15% by weight, (a):(b) was mixed at 1:3.
to create a 1.5% by weight slurry water consisting of 50% by weight of polypropylene and 50% by weight of glass fibers, and then dilute this slurry water with water to make the slurry concentration 0.4% by weight. A web with a basis weight of 260 g was produced using a hand sheet machine. A fiber-reinforced thermoplastic resin sheet having a thickness of 2 mm was prepared in exactly the same manner as in Example 1. The properties of this sheet are shown in Table 3.

[Table] Example 2 (a) 3.0% by weight slurry made of polypropylene with an MFI of 14 (average diameter of interpolated spheres: 0.3 mm) and 0.2% by weight of an amine-type nonionic surfactant added to this polypropylene. (b) A mixed slurry water of 3.6% by weight of polypropylene and talc obtained by adding 20% by weight of talc (average diameter of interpolated spheres 0.5 mm) to polypropylene to this slurry water, (c ) 80% by weight of glass fiber with a fiber diameter of 10 μm and fiber length of 6 mm and 20% by weight of glass fiber with a fiber diameter of 13 μm
(b): Mix (c) at a ratio of 1:3 to make 50% polypropylene by weight.
and 50% by weight of reinforcing fibers (talc is 5% by weight based on the total weight of polypropylene and reinforcing fibers)
A slurry water of approximately 1.7% by weight consisting of . A fiber-reinforced thermoplastic resin sheet having a thickness of 2 mm was prepared in exactly the same manner as in Example 1. The properties of this sheet are shown in Table 4.

[Table] Example 3 (a) A pulp-like nylon 66 resin with a main fiber length of 3 mm and a polyethylene oxide-polyacrylamide type dispersant applied to this nylon 66 resin.
3.5% by weight slurry water with 0.15% by weight added;
(b) 70% by weight carbon fibers with a fiber diameter of 8 μm and a fiber length of 6 mm, and carbon fibers with a fiber diameter of 10 μm and a fiber length of 25 mm,
To this mixed carbon fiber, 0.2% by weight of a polyethylene glycol ester type dispersant and 0.2% by weight of mixed reinforcing fiber slurry water made by adding 10% by weight of a polysodium phosphate thickener in addition to this were added. After preparation, (a):(b) was mixed at a ratio of 1:7.5 to obtain 70% by weight of nylon 66 resin and 30% by weight of mixed reinforcing fiber.
A slurry water of approximately 0.59% by weight consisting of Created. Ten sheets of this web were laminated and dehydrated using a press, then dried at 120℃ for 1 hour, heated for 15 minutes using a sheet forming press at a temperature of 280℃ and a pressure of 10Kg/ ^cm2 , and then temperature 25℃, pressure 15
A fiber-reinforced thermoplastic resin sheet with a thickness of 1.5 mm was prepared by cooling for 20 minutes under the condition of Kg/cm ² . The properties of this sheet are shown in Table 5.

〔Effect of the invention〕

As explained above, the fiber-reinforced thermoplastic resin sheet of the present invention has good mechanical properties,
Since it has the excellent effect of providing a fiber-reinforced thermoplastic resin sheet with excellent sheet surface smoothness and deep drawability, its industrial utility value is extremely high.

Claims (1)

[Scope of Claims] 1 (A) Thermoplastic resin, (B) 60% to 95% by weight of reinforcing fibers with a fiber diameter of 3 μm to 13 μm and a fiber length of 3 mm to 7 mm, and a fiber diameter of 6 μm to 20 μm and a fiber length of 7 mm to 50 mm. 40% to 5% by weight of reinforcing fibers, and (A) is 40% to 80% by weight and (B) is
A fiber-reinforced thermoplastic resin sheet comprising a mixture of 60% to 20% by weight. 2 Based on the total weight of (A) and (B), (C) at least one inorganic or (and) organic filler from 1% by weight
The sheet according to claim 1, wherein 50% by weight is added.