JPH0340058B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a fiber reinforced resin body (FRP).

[Prior art] Fiber reinforced resin (FRP), which is made by impregnating reinforcing fibers such as glass fiber mat with liquid thermosetting resin and curing the resin, is used for various purposes such as automobile parts, bathtubs, boat hulls, etc. The injection molding method is the resin injection molding method (referred to as the RI method).
However, as a press molding method, the Matsushido die method (MD
method) is mainly used and mass-produced.

To obtain FRP of a certain quality, chopped strand mats (CM), which are made of short cut glass fiber bundles, and contained strand mats (CSM), which are made of long glass fiber bundles, are widely used as reinforcing fibers. .

[Problem to be solved by the invention] Using CM or CSM as reinforcing fibers, RI method,
When attempting to manufacture FRP with a deeply curved shape (hereinafter referred to as deep-drawn shape) using the MD method, the fit between the pine and the mold may be poor, or the glass fiber bundles that make up the pine may be damaged due to external forces received during molding. Due to this movement, the distribution of glass fiber bundles in the mat becomes uneven, or tends to be arranged in one direction. This phenomenon is particularly likely to occur at the corners of deep-drawn shapes, and sometimes the pine will break, resulting in areas where no glass fiber bundles are present, resulting in a decrease in the strength of the resulting FRP and quality defects such as cracks that occur at the corners. Cause.

In order to solve these difficulties, we developed a cutting product of glass fiber bundles (chopped strands, hereinafter referred to as CS).
Preformed matte obtained by spraying preformed matt with a binder into a mold having a predetermined shape has been used as a reinforcing fiber, but the molding method using preformed matt (referred to as the preformed matting method) is as follows. It has the following disadvantages.

When using the preform mat method, uneven distribution of reinforcing fibers can be prevented to some extent, but
This method requires time and effort, and has the disadvantage that it is difficult to achieve a completely uniform distribution of reinforcing fibers. That is, preformed mats are manufactured by simultaneously spraying CS and a binder onto a mold having a predetermined shape, but in the case of a deep-drawn mold, the corners of the mold, the vertical parts of the mold, etc. Attachment of CS to
Deposition tends to be insufficient.

In addition, in order to disperse CS along a predetermined curved surface, the preform mat has a CS of 25
It becomes necessary to use a short one of ~50 mm.

When the CS becomes shorter, the CS tends to move and be arranged in one direction during FRP molding, which tends to reduce the strength of the FRP. CM,
It is necessary to add a large amount of binder (approximately 10 wt% to CS) compared to CSM. Therefore, when preform mats are used as reinforcing fibers, the obtained
The transparency and water resistance of FRP tend to decrease.

The present invention is a new proposal based on research to solve these problems of the prior art, and it is a glass fiber mat that facilitates the production of homogeneous deep-drawn FRP (fiber reinforced resin) and a homogeneous The purpose of this invention is to provide a method for manufacturing FRP having a deep drawing shape.

[Means for Solving the Problem] In order to achieve the above object, in the present invention, a long glass fiber bundle having a length of 30 cm or more has a radius of curvature of 1.5 to 1.5 to 70% along its length.
Glass is deposited in a 20 cm curved shape, and these glass fiber bundles are bonded together with a binder made of thermoplastic resin with a softening point of 60 to 200 degrees Celsius measured by the ball ring method. FRP is manufactured by preforming the fiber mat with a softened binder to give it a desired curved shape, and then impregnating it with a liquid thermosetting resin and curing the resin.

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

In the present invention, the length is 30 cm or more, preferably 60 cm
A long glass fiber bundle of the above length is used. If this length is too short, the glass fiber bundle will move easily during FRP molding, and it will be necessary to use a large amount of binder.
The glass fiber bundle has a thickness of 9 to 25μ, preferably
20-200, preferably 30, 13-22μ glass fibers
A fiber bundle of ~150 fibers is suitable.

If the thickness of the glass fiber bundle is too small, the glass fiber bundle will easily move when impregnated with resin, and if the thickness is too large, the surface smoothness of the obtained FRP will be easily lost.

Arco is a sizing agent that should be added to glass fibers.
0.02-0.3wt% lubricant like 185 (trade name),
A liquid material containing preferably 0.05 to 0.2 wt%, 1.5 to 5 wt%, preferably 0.2 to 4 wt% of a film forming agent such as a self-emulsifying polyester resin, and 0.1 to 0.3 wt% of a coupling agent such as a silane coupling agent. It is desirable to use a sizing agent, and the amount of the sizing agent added is suitably 0.1 to 0.5 wt% as a solid substance.

Note that if transparency is required for FRP, it is also possible to use a sizing agent containing only a coupling agent.

In the present invention, the long glass fiber bundles described above are piled up in a mat shape, and a binder described later is applied to bond the glass fiber bundles together.

Industrially, a bundle of glass fibers is fed onto a conveyor that moves at a predetermined speed in the longitudinal direction, and is allowed to fall and pile up, and preferably about 40 to 200 meshes of a powdery binder is added thereto. The binder can be added at the same time as the glass fiber bundle or after the glass fiber bundle is supplied. The amount of deposited glass fiber bundles is 300~
A suitable amount is 600 gr/m ² , preferably 400 to 500 gr/m ² . If this amount is too large, the reforming process (preforming process) for shaping the glass fiber mat into a desired curved shape becomes difficult, and if this amount is too small, productivity will decrease.

Long glass fiber bundles are randomly deposited in a curved shape on the conveyor, and the radius of this curvature depends on the moving speed of the conveyor, the falling speed of the glass fiber bundle, the thickness of the glass fiber bundle, the rigidity, etc. Determined. In the present invention, these conditions are determined so that the radius of curvature is 1.5 to 20 cm, preferably 2 to 15 cm in a portion of 7C% or more, preferably 80% or more of the length of the glass fiber bundle.

Note that such conditions can be determined experimentally.

If the radius of curvature is larger than the above range, the glass fiber bundle is likely to be misaligned during FRP manufacturing, and if the radius of curvature is smaller than the above range, reforming becomes difficult, and during reforming, the mat is likely to be partially cut. .

As a binder, the Ball Ring method (Ball Ring method) is used.
Softening point measured by method) is 60-200℃, preferably
Use thermoplastic resin at 80-150℃. By using such a binder, it is possible to obtain a mat with good handling properties and deep drawability in the preforming process.

Also, it has high solubility in matrix resin,
It is undesirable to use a binder whose binding strength is significantly reduced when the mat is impregnated with the matrix resin.

The binder is selected depending on the type of resin (matrix resin) with which the mat of the present invention is impregnated, and the following are suitable binders that satisfy the above conditions.

When the matrix resin is an unsaturated polyester resin or a polyurethane resin: A polyester resin, preferably an isophthalic acid-modified alkyd resin, or a bisphenol-modified alkyd resin, particularly preferably an isophthalic acid-modified alkyd resin When the matrix resin is Metone resin (trade name): Polyethylene or polypropylene When the matrix resin is a phenolic resin Novolac resin Alkyd resins and novolac resins are cured by heating when a curing agent or curing accelerator such as organic peroxide or hexamethylene diamine is added, and are thermoset. However, if it does not contain these, it will not harden but will soften even when heated, and will function as a thermoplastic resin.

In the present invention, the modified alkyd resin and novolak resin refer to those which do not contain a curing agent or curing accelerator as described above.

By using such a binder,
During FRP molding or preforming as described below, the glass fiber bundles will not shift and the distribution of the glass fiber bundles will not be uneven, and the mat can be preformed into the desired deep drawing shape. It becomes even more noticeable.

The mat of the present invention is produced by heating the glass fiber bundles to which a binder has been added to harden the binder and bonding the glass fiber bundles together. At this time, it is desirable to apply pressure using a pair of rolls or the like.

The bulk density of the mat in an unloaded state and the bulk density when a predetermined pressure is applied to the mat are determined by the above-mentioned clamping pressure during the production of the mat and the elastic repulsive force of the glass fiber bundles that make up the mat. Particularly desirable is pine whose bulk density, as measured by the measuring method, is in the following range.

Thickness 3 on the entire surface of mats larger than 30cm x 30cm
Bulk density (weight/area x thickness of the pine) measured with a steel plate of mm in diameter placed on it (in this case, the load the pine receives is approximately 3gr/ ^cm3 , which is virtually no load)
is 0.08~0.25gr/ ^m3 preferably 0.10~0.18gr/ ^cm3
The bulk density when applying a load of about 30gr/ ^cm2 to the pine is 0.3~0.42gr/ ^cm3 , preferably 0.36~
0.4gr/ ^cm3 .

The elastic repulsive force of the glass fiber bundle is determined by the thickness of the glass fibers, the number of bundles, the type and amount of the sizing agent, the type and amount of the binder, and the length of the glass fiber bundle. The specifications of pine having a range of bulk densities can be easily determined experimentally.

The mat of the present invention is composed of long glass fiber bundles,
In addition, since the mat itself has a nearly planar shape, the amount of binder added to the glass fiber bundle is sufficient to be about 2 to 6 wt%, and the glass fiber bundles are sufficiently bonded together, so that when forming FRP, the glass fiber bundle No movement (weld) occurs.

When producing FRP having a deep drawn shape using the glass fiber mat of the present invention as a reinforcing fiber, the mat is heated to 100 to 210°C, preferably 150 to 180°C, and then pressurized using a pair of molds, It is appropriate to perform pre-forming to give a predetermined shape in advance, but it is also possible to heat the pine with hot air or spray a solvent onto the pine to harden the binder, and then manually bend the pine. It is also possible to carry out preforming. .

Using the mat of the present invention, FRP is manufactured by the known RI method or MD method. The liquid thermosetting resin used at this time is unsaturated polyester resin,
Epoxy resin, metone resin, polyurethane resin,
Although a phenolic resin or the like can be used, it is practical to use an unsaturated polyester resin.
The amount of resin added is appropriately determined so that the proportion of glass fiber mat in the FRP is 20 to 70 wt%, preferably 30 to 60 wt%.

By using a binder as mentioned above,
It is possible to prevent a decrease in the bonding strength of the binder caused by the liquid thermosetting resin during FRP production, and to further reduce welding of the glass fiber bundles.

[Function] A long glass fiber bundle with a length of 30 cm or more is deposited in a shape with a radius of curvature of 1.5 to 20 cm in 70% or more of the length along the length,
By bonding these fiber bundles with a binder made of thermoplastic resin with a softening point of 60 to 200°C measured by the ball ring method, the glass fiber bundles are bonded together with a small amount of binder to form a mat. Furthermore, when this mat is used as a reinforcing material for FRP, welding of glass fiber bundles is reduced, and preforming of this mat is facilitated.

Furthermore, by preforming such a mat into a desired shape with the binder softened, and then impregnating it with a liquid thermosetting resin and then curing the resin, the shape of the glass fiber bundle during molding is improved. Make the weld even smaller.

[Example] 3.5wt% self-emulsifying polyester emulsion, 0.1wt% Arco 185, 20μ thick glass fiber,
A sizing agent containing 0.2wt% of A174 is used as a solid content.
A continuous glass fiber bundle with a concentration of 0.35wt% was dropped onto a moving conveyor at a rate of 450gr/ ^m2 , and the glass fiber bundle had a concentration of 90% along its length.
A pine-like material deposited in a curved shape having a radius of curvature of 2 to 10 cm was obtained in the above portion.

Thermoplastic resin powder (50 to 150
4wt% of pine was added and heated to 210°C to produce pine with a bulk density of 0.14gr/cm ³ when unloaded and 0.38gr/cm ³ when a load of 30gr/m ² was applied. Obtained.

The softening point of the thermoplastic resin binder as measured by the Ball Ring method was 150°C.

This mat was heated to 180°C and pressed between a pair of molds to pre-form it into a dish shape of 80 cm x 80 cm and height 10 cm, and impregnated with unsaturated polyester resin so that the weight of the mat in FRP was 35 wt%. Using the MD method, we were able to obtain FRP with less welding and good water resistance.

Example 2 The same results as in Example 1 were obtained by using a glass fiber bundle cut to a length of 60 cm instead of the continuous glass fiber bundle of Example.

[Effects of the Invention] A homogeneous FRP with small welds and good transparency and water resistance can be obtained.

Claims (1)

[Claims] 1 A long glass fiber bundle with a length of 30 cm or more has a radius of curvature of 70% or more along its length.
They are deposited in a curved shape of 1.5 to 20 cm, and these glass fiber bundles are bonded together with a binder made of thermoplastic resin with a softening point of 60 to 200°C measured by the ball ring method. Fiber reinforcement characterized by preforming a glass fiber mat with a softened binder into a desired curved shape, and then impregnating it with a liquid thermosetting resin and curing the resin. Method for manufacturing resin bodies.