JPS5896628A - Manufacture of reinforced plastics - Google Patents

Abstract

PURPOSE:To obtain a reinforced plastic of excellent bite of glass fiber and good autometering characteristics, with outstanding kneading workabiligy, by blending a specific glass chopped strand with a resin followed by a forming. CONSTITUTION:The objective plastic can be obtained by blending, with a thermosetting or thermoplastic resin, a glass chopped strand containing >=90wt% of a strand having an average length 1.0-2.0mm. and a weight per length >=0.4mg/mm., with the aggregate bulk density >=0.70g/cm<3>, and then carrying out a kneading and forming by an automatic feeder and an extruder, respecively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing glass fiber reinforced plastics (hereinafter referred to as FRP) using a mechanical device such as an injection molding machine. More specifically, by using glass fiber strands with short fiber length and excellent cohesiveness (hereinafter referred to as ``chietsubuto strands''), the measurement error during automatic measurement of chief bud strands in FRP manufacturing is small, making it easier to knead. The present invention aims to provide a method for manufacturing FRP with excellent properties. It has been well known that physical properties such as strength 2 modulus of elasticity and heat deformation temperature of molded products can be improved by adding chisel strands to thermosetting resins or thermoplastic resins.

Strands with fiber lengths of 13cm, 6cm, and 3cm are generally known. However, when using the above-mentioned chisel strands in thermosetting resin or thermoplastic resin for new molded products, especially small precision molded products, the molding shrinkage rate is affected by the flow orientation of the glass fibers during molding. This has the major disadvantage that directional properties occur, causing warping and twisting of the molded product, and the strength of the molded product also becomes directional.

On the other hand, in recent years, the mixing ratio of = material and resin is kept constant, and an automatic feeding device is used to continuously extrude the
By supplying the packing ridge filler into the trout fishing machine, pellets or molded products with reinforced wood are produced, and the efficiency is dramatically improved.
If the material is not introduced from the automatic feeding device into the extruder, the strength variation will increase, resulting in a decrease in the reliability of the material.
This has the fatal drawback of producing many defective products. Conventional 13■, 6■, and 3-pronged chitbuto strands have relatively good automatic measurement properties, but there are also cases where attempts have been made to use directional so-called chitbuto strands.

Since only a product with extremely poor cohesiveness could be obtained, it became a cotton-like product in which the single fibers were entangled with each other, making it impossible to handle with an automatic weighing machine and having very poor kneading workability with resin. etc. below 3m/s.

As a result of intensive research on the shape of Cheet's brand, which has good penetration into glass fiber and good automatic measurement, we found that the average length is 1.0 m or more and less than 2.0 cm, and the weight per unit length is 0.
．． It has become possible to realize highly coherent chipped strands that are composed of 90% by weight or more of 04q/- or more strands and have a bulk density of 0.7 Of/as or more. In addition, this product has good automatic metering properties and is also excellent in cross-wire work with resin.
Furthermore, the mechanical strength of the molded product is the same as when using 13cm, 6cm, and 3m Cheetzbut strands, and it has been found that there is little directionality even if the wires are crossed for a short time, leading to the present invention.

If the length of the Cheetzbut strand is 1.0- or less.

Because the mechanical strength of Chiang molded products is low, 梼71,
- Not very useful as scooping material.

Even if the average length of the strand is 1.0 m or more and less than 2.0 m, the weight per strand unit length is 0.04 q/■
Many of the following strands have a bulk density of 0.70 f/- or less, and the strands with poor cohesiveness are often entangled with Qbeme single fibers, which may cause nozzle clogging in the injection molding machine. The following examples, handleability when mixing trand, and mixability (1) Resin that cannot be used because automatic weighing performance and cross-wire workability deteriorate This refers to the discharge stability of the cheatsbut strands, the biting ability, etc. when mixed with
1) Handling efficiency when putting the cheats butt strands into the hopper of a kneading machine (means the biting and mixing properties of the cheats butt strands during compound mixing work.Length and weight of the cheatsbut strands) Divide the sample Chirobutsu strand into four parts and extract 1.00% from one of them.
Zero strands were randomly selected and their lengths were measured using a magnifying projector, and their weights were measured using an analytical balance. For automatic weighing, put the cheatsbut strands in a volumetric automatic weighing machine (Acrison 105z feeder) and measure the amount dispensed in 1 minute 50 times.
The fluctuation rate was calculated using the following formula.

The bulk density of the Cheetroot strands was calculated by measuring the volume of 100 grams of Cheetroot strands and using the following formula.

Example 1 Cheatsbut strands and polybutylene terephthalate according to the present invention shown in sample numbers 1 to 3 were supplied to the hopper of a single-screw pent extruder at a weight ratio of 30:70.Glass fiber reinforced polybutylene terephthalate resin pellets was created. At this time, the biting ability of the Cheetroot strands in a part of the hopper was observed.

The physical properties of a molded article molded using the obtained glass fiber reinforced pellet were measured. These results are shown in Table 1. Similarly, 13■ was used as a comparative example.

The results were also shown in Table 1 using conventional Cheetbutt strands with low bulk densities of 6■, 3■ and 1.5 snow and measured in the same manner as described in the Examples. 1st
From the results shown in the table, the Cheetroot strands of Examples according to the present invention had good automatic weighing properties.

It is clear that the wire crosstalk workability is excellent.

Example 2 Bulk molding (hereinafter referred to as 'F') was made into a putty by kneading the composition shown in Table 2 under the conditions shown in Table 3 using a niegoo.
Table 4 Sample numbers 1 to 3 using the Cheetzbut strands according to the invention as glass fibers in the BMC (referred to as BMC) were supplied by a stuffer to the equipment tank injection molding machine, and as shown in Table 3. Depending on the conditions shown, 200■ (width) x 600■ (length) x 60 haze (height)
A box-shaped product was manufactured. Test pieces were cut out in two directions, perpendicular to the flow direction of the resin of this molded product, and a 1.5-inch Cheetz buto strand with poor cohesiveness and low bulk density was used, and the method described in the example was used. The physical properties of the molded products produced by the same method as above were measured, and the results are shown in Table 4. From the results shown in Table 4, it was found that the cheatbute strands according to the present invention can be easily and uniformly dispersed in the compound when mixed. It is also clear that the difference in strength of the molded product between the direction of flow of the resin and the direction perpendicular to it is small, which is superior to the strength of molded products using conventional 6-inch and 3-inch Cheetzbut strands.

7〒111, -1□f--5 @2 Table 3 Table 114 Procedural Amendment (Method) % Formula % 1. Indication of the case 1982 Patent Application No. 194567 2. Name of invention Reinforced plastics Manufacturing method 3, relationship with the case of the person making the amendment Patent applicant address (residence) 13-7 Uchikanda-chome, Chiyoda-ku, Tokyo 101 Name Representative Koga Ya 4DL 1. )\, - 4. Date of amendment order: March 30, 1980 5. "Title of the invention" column of the specification to be amended, as well as the application and specification.

6. Contents of the amendment (1. The name of the invention has been corrected to "Method for manufacturing reinforced plastics."

(2) Engraving of application and specification, (more than 匈%+zt'c1i)

Claims (1)

[Claims] 1. Contains 90% by weight or more of strands with an average length of 1.0 to less than 2.0 and a weight per unit length of 0.04 q/w or more, and the bulk density of the aggregate is 0.7Of A method for producing glass fiber reinforced plastics, characterized by using glass fiber reinforced plastic strands having a diameter of /j or more.