JPH0530782B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fiber reinforced thermoplastic resin body (FRTP).
This invention relates to a method for producing a molding material useful for the production of.

[Conventional technology]

FRTP is manufactured by injection molding using pellets (fiber-containing pellets) containing reinforcing fibers such as glass fibers and thermoplastic resin.

Fiber-containing pellets are usually produced by kneading cut reinforcing fibers (for example, chopped strands, abbreviated as CS) and thermoplastic resin under heat, but the reinforcing fibers are likely to be shredded during the kneading operation. , therefore, the FRTP obtained using this pellet
The problem is that the strength of the material decreases.

In order to overcome the above-mentioned difficulties, a method has been proposed in which continuous glass fiber bundles such as strands or rovings are coated with thermoplastic resin and then cut to produce fiber-containing pellets (referred to as the long length method). There is.

Continuous glass fiber bundles are used in the long method, but industrially, a cylindrical wound body (cylindrical wound body) of glass fiber bundles is used; It is drawn out from the roll and continuously fed to a thermoplastic resin coating device.

If the glass fiber bundle contains moisture, this moisture will evaporate during FRTP molding and the performance of FRTP will deteriorate. Therefore, the cylindrical wound body should be a pre-dried one, such as a direct-wound roving such as Type 30. A rolled body is used.

[Problem to be solved by the invention]

The conventional long length method has the following problems.

While the glass fiber bundle is pulled out from the dried cylindrical roll and sent to the thermoplastic resin coating device, the glass fiber bundle also becomes fluffy, resulting in uneven adhesion of the resin to the glass fiber bundle, which leads to problems with FRTP. Quality tends to vary, and the glass fiber bundles may break. In particular, this tendency is seen as a sizing agent.
This is noticeable when using materials containing acrylic resin, urethane resin, or AS resin. Furthermore, when the glass fiber bundle is pulled out, the glass fiber bundle is not completely straight, and distortions due to twisting and curvature remain, resulting in uneven adhesion of the thermoplastic resin and variations in the quality of FRTP. Cause. When a glass fiber bundle is pulled out from a cylindrical wound body, such distortion occurs in the drawn glass fiber bundle when the glass fiber bundle is pulled out in the longitudinal direction of the wound body.
This is thought to be due to one twist per circumference of the cylindrical spiral body, and by supporting the cylindrical spiral body rotatably around the axis of the cylinder and pulling it out,
Attempts have been made to prevent the twisting caused by the above-mentioned drawing, but it is difficult to completely eliminate residual strain and obtain a homogeneous FRTP.

An object of the present invention is to provide a method for producing a molding material for FRTP coated with a thermoplastic resin, which allows a homogeneous FRTP to be obtained without fuzzing or cutting when pulling out a glass fiber bundle. .

[Means to solve the problem]

In order to achieve the above object, the present invention includes a step of applying a sizing agent to a large number of glass fibers pulled out from a bushing and converging them into a glass fiber bundle, and a step of reciprocating the glass fiber bundle along a rotating axis. The step of engaging the guide member and winding it around the shaft to form a cylindrical rolled body, the moisture content of the rolled body being
A molding material is produced by the steps of drawing out the glass fiber bundle from the rolled body in a state of 0.5 to 13 wt%, drying the drawn out glass fiber bundle in a running state, and then coating it with a thermoplastic resin.

1000m in dry condition as glass fiber bundle
The weight per unit is 300~10000gr, preferably 500~
Use 5000gr.

Next, the present invention will be explained in more detail.

A sizing agent is applied to a large number of glass fibers pulled out from the bushing, and the fibers are bundled by a sizing member.

Glass fibers having a diameter of 3 to 23 microns, preferably 9 to 16 microns can be suitably used.

Prevents fuzzing and thread breakage when manufacturing glass fiber bundles or when pulling out glass fiber bundles from rolled bodies to improve workability, and improves compatibility between glass fibers and thermoplastic resin. Get used to it
In order to improve the strength of FRTP, a sizing agent containing a coupling agent, lubricant, and film forming agent is used.

As the coupling agent, silane coupling agents such as aminosilane, epoxysilane, and vinylsilane, or titanium-based coupling agents, particularly silane coupling agents, are preferably used.

As the lubricant, fatty acid amides, nonionic surfactants, etc. can be suitably used. In addition, particularly remarkable effects can be obtained when urethane resin, acrylic resin, or AS resin is used as the film forming agent.

The concentrations of the coupling agent, lubricant, and film forming agent in the sizing agent are 0.05 to 0.8 wt%, 0.05 to 0.5 wt%, respectively.
0.5 to 10 wt%, and 0.01 to 2 wt%, preferably 0.1 to 0.8 wt% of the sizing agent in the glass fiber as a solid content.
It is appropriate to grant it. The glass fibers to which a sizing agent has been added are bundled into a glass fiber bundle according to a conventional method and guided to a guide member.

The guide member is reciprocated along the rotating shaft, the glass fiber bundle is wound into a cylindrical shape to form a roll, and the glass fiber bundle is then pulled out from the roll and sent to the next step.

If the rolled body contains a large amount of moisture, it should be pre-dried before being pulled out to reduce the moisture content to 0.5-13wt%.
The content is desirably 3 to 8 wt%.

If this moisture content is too high, drying in the drying process described below will be insufficient, which tends to cause quality defects in FRTP.If this moisture content is too low, effects such as preventing fluffing will be insufficient, and migration tends to become large. By drying the pulled out glass fiber bundle while it is running, it is possible to dry it uniformly and obtain a glass fiber bundle free from distortion.

Drying is preferably carried out in an oven maintained at 100-300°C, preferably 120-200°C, at 5-200m/min.
It is preferable to carry out the drying while running the spun fiber bundle at a speed of about 10 to 100 m/min, but it is also possible to dry by high frequency heating or the like.

The glass fiber bundle is then coated with a thermoplastic resin.

Although there is no particular limitation on the method of application, it is preferable to run the glass fiber bundle through a thermoplastic resin melt, apply the melt to the surface of the fiber bundle, and squeeze out excess resin. can be dressed.
The amount of resin deposited is determined depending on the type of resin and the use of the molding material produced by the above method, and the glass fiber content is preferably 20 to 80 wt%.
It is appropriate to set it at 60wt%.

[Effect]

Although the function of the present invention is not fully clear, it is thought to be approximately as follows. When a large number of glass fibers drawn from a bushing are added with a sizing agent and converged to form a glass fiber bundle, the glass fibers in the fiber bundle are tightly and tightly attached to each other in parallel to each other.

When this glass fiber bundle is engaged with a guide member that reciprocates along a rotating shaft and wound around the shaft to form a cylindrical wound body, the glass fibers are wound in a state in which they are in close contact with each other.

If the wound body is dried in this state as in the prior art, a migration phenomenon occurs in which the sizing agent migrates to the surface as the moisture evaporates.

Due to migration, from a macroscopic perspective, the content of the sizing agent increases in a portion closer to the surface of the wound body.

In addition, although moisture moves through capillary action, the distribution of fibers in the rolled body is not uniform, so passages where moisture can easily move and areas where moisture cannot move are mixed irregularly in the rolled body. Therefore, the distribution of the focus that moves with this moisture becomes microscopically non-uniform.

In this state, the glass fiber bundles are wound into a cylindrical shape in a curved shape, dried in close contact with each other, and fixed to each other with a sizing agent.

For this reason, the glass fiber bundle pulled out from the wound body has variations in the content of the sizing agent along the length direction, and the sizing agent is dried and solidified while remaining in a curved shape, resulting in twisting, Curves remain, and when the fibers are pulled out, they are subjected to large local stresses, and areas with a large amount of sizing agent are difficult to peel off, resulting in local fiber breakage, and curved areas are rubbed by guides, etc.
It is thought that it causes fluff.

On the other hand, when using the method of the present invention, the glass fiber bundle is drawn out with a moisture content of 0.5 to 13 wt%, and the sizing agent is not dried and solidified, so the drawn glass fiber bundle is easily drawn out. It is considered that the fibers are deformed into a straight shape, the fibers are not cut, and the variation in the distribution of the sizing agent during the drying process is small, resulting in a uniform fiber bundle.

〔Example〕

Add 4wt% of PP emulsion and 0.5wt% of lubricant to the 13μ thick glass fiber pulled out from the bushing.
A sizing agent containing 0.6 wt% of aminosilane was added as a solid content of 0.4 wt%, and 3200 fibers were bundled to form a glass fiber bundle.

This glass fiber bundle has an inner diameter of 16 cm, an outer diameter of 26 cm, and a height of
It was rolled into a 26 cm cylinder and pulled out at a speed of 30 m/min with a moisture content of 8 wt%.

Then, it was dried by passing through an oven kept at 200°C, and 150wt% PP was applied to the glass fibers, and the fibers were cut into 1cm pieces to be used as a molding material.

No fluffing or thread breakage occurred during the production of the molding material. Also, using this molding material, ASTM.
A test piece of No. D-256 was manufactured and the measured impact strength was 45 kg-cm/cm.

[Comparative example]

The same experiment as in the example was carried out by drying the same rolled body as in the example until the water content was 0.1 wt% or less, applying resin to the drawn glass fiber bundle as it was.

Fuzzing frequently occurred, and the impact strength of the test piece obtained was 40 kg-cm/cm.

〔Effect of the invention〕

A homogeneous molding material can be obtained without fluffing or thread breakage during the production of the molding material, and high-strength FRTP can be obtained using this molding material.

Claims (1)

[Scope of Claims] 1. A step of applying a sizing agent to a large number of glass fibers pulled out from a bushing and converging them into a glass fiber bundle, and engaging the glass fiber bundle with a guide member that reciprocates along a rotating axis. In the process of tightening and winding it around the shaft to form a cylindrical roll, the water content of the roll is
A method for producing a molding material, comprising the steps of drawing out a glass fiber bundle from a rolled body in a state of 0.5 to 13 wt%, drying the drawn glass fiber bundle in a running state, and then coating it with a thermoplastic resin. 2 The dry weight of the glass fiber bundle is 300
2. The method for producing a molding material according to claim 1, wherein the molding material has a particle size of 10000gr/1000m.