JP2002331523A - Fiber-reinforced resin molding and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced resin molding which is excellent in strength and impact resistance, light in weight, and low in production costs and has a high grade feel and a method for producing the molding. SOLUTION: In the fiber-reinforced resin molding, the lengths of reinforcing fibers on the surface side are greater than those on the back side. Preferably, a layer 2 on the surface side of the molding contains no reinforcing fibers or contains the reinforcing fibers 2-6.5 mm in length, and a layer 3 containing the reinforcing fibers 10-30 mm in length is laminated on one surface of the layer 2. The fiber-reinforced resin molding is produced by compression molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced resin molded article which is a molded article of a thermosetting resin reinforced with reinforcing fibers such as glass fibers and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a fiber-reinforced resin molded product (hereinafter, sometimes referred to as a molded product) used for a bathtub, a waterproof pan, a wall panel, etc. is formed, for example, by compressing a sheet molding compound (hereinafter abbreviated as SMC). It was manufactured by molding. SMC means that a reinforcing fiber is impregnated with a paste-like mixture of a thermosetting resin such as an unsaturated polyester resin and an initiator, a filler, etc., and both sides are covered with a film to form a sheet. For a certain period of time to increase the viscosity by a chemical reaction to form a sheet having no tackiness. Conventionally, as the reinforcing fiber, for example, a short glass fiber cut to a length of 6.5 mm or less or a long glass fiber cut to a length of 10 to 30 mm has been used.

[0003]

The compression-molded article using the short glass fiber is excellent in surface gloss, surface smoothness, transparency, decorating property, etc., but is inferior in strength such as impact resistance. There was a disadvantage that it was difficult to reduce the weight of the molded product.
Further, there is a disadvantage that the manufacturing cost of the molded product is high. On the other hand, compression molded products using the above glass long fibers,
It is advantageous in that it has excellent strength such as impact resistance, is easy to reduce the weight of molded products, and has low manufacturing costs.
However, there is a defect that the surface gloss, surface smoothness, transparency, decorating property, and the like of the molded article are inferior.

Accordingly, the present invention provides a fiber-reinforced resin molded article having excellent strength such as impact resistance, surface smoothness, etc., a reduction in weight and a reduction in production cost, and a high quality appearance, and a method for producing the same. The task is to provide

[0005]

The fiber-reinforced resin molded article of the present invention contains a thermosetting resin and a reinforcing fiber, and the fiber length of the reinforcing fiber is longer on the back side than on the front side.

[0006] The fiber-reinforced resin molded product is preferably provided on one side of a layer containing a thermosetting resin and a reinforcing fiber having a fiber length of 2 to 6.5 mm with a thermosetting resin and a fiber length of 10 to 30 mm.
and a layer containing a reinforcing fiber of mm.

[0007] The fiber-reinforced resin molded product preferably comprises a thermosetting resin and a reinforcing fiber having a fiber length of 10 to 30 mm on one side of a layer containing a thermosetting resin and containing substantially no reinforcing fibers. Is characterized in that a layer containing the same is formed.

The method for producing a fiber-reinforced resin molded article of the present invention comprises a molding material containing a thermosetting resin and substantially no reinforcing fibers or a thermosetting resin and a reinforcing fiber having a fiber length of 2 to 6.5 mm. Molding material, thermosetting resin and fiber length 10-30m
m and a molding material containing reinforcing fibers are arranged in a molding die,
It is characterized by compression molding.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments will be described to make the present invention easier to understand. Such an embodiment shows one embodiment of the present invention, and does not limit the present invention. It can be arbitrarily changed within the scope of the present invention. The fiber-reinforced resin molded article of the present invention is a fiber-reinforced resin molded article composed of at least a thermosetting resin and a reinforcing fiber, wherein the fiber length of the reinforcing fiber is lower than the front side of the molded article. This is a fiber-reinforced resin molded product characterized by having a long side. The surface means a surface of a fiber-reinforced resin molded product used as a product.

FIG. 1 is a sectional view showing one embodiment of a fiber-reinforced resin molded product of the present invention. Examples of the form of the fiber-reinforced resin molded product in which the fiber length of the reinforcing fiber is longer on the back side than on the front side include the following. Preferred first
In the example, a layer containing at least a thermosetting resin and a reinforcing fiber having a fiber length of 2 to 6.5 mm is formed as a layer 2 on the front side, and a thermosetting resin is formed on the back side of the layer 2 on the front side. This is a fiber-reinforced resin molded product in which a layer containing at least a reinforcing fiber having a fiber length of 10 to 30 mm is formed as a layer 3 on the back side. Another preferred example is that a layer containing at least a thermosetting resin and containing substantially no reinforcing fibers is formed as the front layer 2, and the thermosetting resin and the fiber length are formed on the back surface of the front layer 2. This is a fiber-reinforced resin molded product in which a layer containing at least a reinforcing fiber of 10 to 30 mm is formed as a layer 3 on the back surface side. It is preferable that the layer 3 on the back side is directly laminated on the back side of the layer 2 on the front side. Further, substantially not containing a reinforcing fiber means that the content of the reinforcing fiber is less than 1% by weight. Although FIG. 1 shows each of the front-side layer 2 and the back-side layer 3 as a single layer, each of the front-side layer 2 and the back-side layer 3 has two or more layers. May be constituted.

The reinforcing fiber is a fibrous material for reinforcing (reinforcing) the thermosetting resin, and examples thereof include inorganic fibers such as glass fiber and carbon fiber, and organic fibers such as aramid fiber. . Among them, when glass fiber is used as the reinforcing fiber, a molded article having excellent impact resistance, chemical resistance, durability and the like can be obtained.

When the surface side layer 2 contains reinforcing fibers, it is preferable to use reinforcing fibers having a fiber length of 2 to 6.5 mm. And the content of the reinforcing fiber in the layer 2 on the surface side is 0 to 20% by weight, preferably 1 to 10% by weight.
If the content is small, the impact strength is not improved, or
This may cause cracks during molding. Fiber length is 2-6.
Since it is as short as 5 mm, the smoothness, gloss, etc. of the surface of the molded article are hardly reduced, but when it exceeds 20% by weight, the smoothness, gloss, etc. of the surface are easily reduced.

The layer 3 on the back side has a fiber length of 10 to 30 mm.
Containing reinforcing fibers. If the fiber length is less than 10 mm, strength, rigidity, cracks during molding, etc. are difficult to improve,
If it exceeds 30 mm, the surface smoothness of the surface-side layer 2, the fluidity during molding, and the filling property into the ribs and the like are likely to decrease. The content of the reinforcing fibers in the layer 3 on the back side is 15 to 40% by weight, preferably 15 to 30% by weight. When the fiber length is long and the content is high, the molded article is excellent in strength such as impact resistance even when the thickness of the layer 3 on the back side is small.

The thickness t _{1 of the} layer 3 containing reinforcing fibers having a fiber length of 10 to 30 mm is preferably 10 to 90% of the total thickness (total thickness) t of the molded article. Fiber length 10
When the thickness of the layer 3 containing the reinforcing fibers of up to 30 mm exceeds 90%, it is difficult to make the surface-side layer 2 a uniform layer. If it is less than 10%, cracks are likely to occur in the molded article during compression molding, and it is difficult to improve impact resistance and the like.

Examples of the thermosetting resin include unsaturated polyester resins and thermosetting resins such as acrylate resins (acrylic resins) such as epoxy acrylate (vinyl ester resin) and urethane acrylate resin. Unsaturated polyester resins, acrylic resins, etc. are preferred as thermosetting resins because they are easily thermoset and give molded articles having excellent chemical resistance and durability. The thermosetting resin is usually cured using an initiator (curing agent). To the thermosetting resin, if necessary, additives such as a curing accelerator, a low-shrinking agent, a release agent, an ultraviolet absorber, a thickener, a dye and pigment, an inorganic filler, and a particulate decorating agent are added. You. Examples of granular decorating agents include colored mica, transparent mica, colored aluminum flakes,
Inorganic flakes such as glass flakes, scaly decorative materials such as colored resin films or cut colored fibers, or ground products such as natural stones or colored resins. It is preferable that the inorganic filler (filler) is contained in each of the front-side layer 2 and the back-side layer 3 in an amount of 30% by weight or more.

Known unsaturated polyester resins can be used. What is an unsaturated polyester resin?
For example, a resin liquid obtained by co-condensing a polyol such as ethylene glycol, an unsaturated polycarboxylic acid such as maleic anhydride and fumaric acid, and a saturated acid such as adipic acid and orthophthalic acid with styrene, It is obtained by adding a monomer having an ethylenic double bond such as methyl methacrylate.

Known additives can be used as an additive to be added to the unsaturated polyester resin and the like. For example, TMPO and TMPB are used as initiators, cobalt naphthenate (6% solution) is used as a curing accelerator, Polystyrene, vinyl acetate resin, methacrylic resin, saturated polyester as a low shrinkage agent, zinc stearate as an internal mold release agent, magnesium oxide as a thickener, aluminum hydroxide, calcium carbonate as an inorganic filler, Glass,
A fine powder of silica or the like having a particle size of several μ to several tens μ is exemplified.

The fiber-reinforced resin molded article of the present invention comprises a thermosetting resin containing a thermosetting resin and substantially no reinforcing fiber or a thermosetting resin and a reinforcing fiber having a fiber length of 2 to 6.5 mm. Molding material containing a thermosetting resin and a reinforcing fiber having a fiber length of 10 to 30 mm (hereinafter sometimes referred to as a back layer material). The sheet material in which the surface layer material and the back surface layer material are pre-laminated is supplied to a molding die and disposed in the molding die, and these molding materials are compression molded to form a thermosetting resin. Can be produced by curing. The surface layer material forms the front layer 2 of the molded article, and the back layer material forms the rear layer 3. Surface layer material including glass fiber, back layer material, for example, a reinforcing fiber and a thermosetting resin liquid, an initiator, an inorganic filler and the like are mixed to form a paste-like mixture, and then the mixture is formed into a reinforcing fiber. It can be obtained as a sheet-shaped or bulk-shaped molding material by mixing with impregnating or reinforcing fibers.

The fiber-reinforced resin molded article of the present invention is, for example,
The back layer material is placed in a molding die, the surface layer material is placed on the back layer material, and then the mold is clamped and compression molded to thermally cure the back layer material and the surface layer material. It can be manufactured by solidifying and bonding, and taking out a molded product from the mold.

The molded article according to the present invention is excellent in impact resistance and the like, and is lightweight and of high quality, so that it can be suitably used as a counter for kitchens and bathrooms.

[0021]

Hereinafter, the present invention will be described in detail. In the following test examples, all “%” and “part” mean “% by weight” and “part by weight”. -Test Examples 1 to 5-In order to clarify the relationship between the configuration of the molded product and the impact resistance and the like, as shown in Table 2, five types of molded products of Test Examples 1 to 5 were manufactured. For that purpose, the surface layer material A, the surface layer material B, and the back surface layer material C having the composition shown in Table 1 were first prepared.

Preparation of Surface Layer Material A: Surface layer material A, which is a composition containing glass fibers having a fiber length of 1/8 inch, was prepared as follows. That is, as shown in Table 1, aluminum hydroxide 65%, low shrinkage agent 5%, curing agent (initiator) 0.3
%, A thickener 0.2%, a release agent 1.0% and a colorant (pigment) 1.5% are mixed with 22% of an unsaturated polyester resin liquid and stirred to form a paste-like mixture, The mixture was prepared by mixing 5% of glass fiber (cut to 1/8 inch length) with the mixture.

Preparation of surface layer material B; aluminum hydroxide 6
Surface layer material B containing no glass fiber was prepared in the same manner as surface layer material A except that 70% of aluminum hydroxide was used instead of 5% and 5% of glass fiber was not used.

Preparation of Back Layer Material C: As shown in Table 1, 40% calcium carbonate, 10% low shrinkage agent, 0.3 hardening agent
%, Thickener 0.2%, release agent 1.0% and coloring agent 1.5
% With 22% of an unsaturated polyester resin liquid and stirred to form a paste-like mixture. The mixture is impregnated with 25% of glass fiber (glass fiber cut to a length of 1 inch) to form a sheet-like material. By doing so, the back layer material C was produced.

[0025]

[Table 1]

Using the surface layer material A, the surface layer material B, and the back surface layer material C, the molded articles of Test Examples 1 to 5 shown in Table 2 were compression molded. For that purpose, a flat-plate molding die for compression molding was prepared. The compression molding conditions of the flat plate are as shown in Table 2,
The temperature of the upper mold (the mold for molding the working surface of the product) is 14
0 ° C, the temperature of the lower mold (the mold for molding the back surface of the product) is 130 ° C, and the pressing force (compression molding pressure) is 80 kg / cm.
^The pressurizing time was 4 to 8 minutes. In addition, the mold closing speed (2nd speed) at the end is 3
The time was set to 0 seconds, and the mold was clamped. The evacuation at that time is -50
The test was performed under a reduced pressure of 0 mmHg. The thickness and total thickness of each of the layer 3 on the back side and the layer 2 on the front side of the molded product can be changed by changing the amounts of the back layer material C, the surface layer material A and the surface layer material B between the molds. Adjusted by

The molded articles of Test Examples 1 to 5 were molded as follows. Molded product of Test Example 1; placing back surface layer material C on the lower mold of flat plate forming die, and placing surface layer material A on back surface layer material C
Were placed on top of each other, and then the upper mold was lowered to close the mold, compression-molded under the molding conditions described above, and the back surface layer material C and the surface layer material A were thermally cured and bonded. As a result, as shown in FIG. 1, a fiber-reinforced resin molded product having a multilayer structure in which the layer 3 on the back side is laminated on one side of the layer 2 on the front side (total thickness is 8 m)
m), the layer 2 on the surface side is made of a cured product of an unsaturated polyester resin and glass fiber (3.18 inches) having a fiber length of 1/8 inch.
mm), and the layer 3 on the back side has a cured product of the unsaturated polyester resin and a fiber length of 1 inch (2 inches).
5.4 mm) of glass fiber, and the thickness fraction of the front side layer 2 is 75% (6 mm thickness), and the thickness fraction of the back side layer 3 is 25% (2 mm thickness). A resin molded product (molded product) was obtained.

Molded product of Test Example 2 having a multi-layer structure in the same manner as in Test Example 1 except that the amount of the back layer material C and the surface layer material A was reduced by half. The product was molded.
The obtained molded product had the same configuration as that of Test Example 1 except that the thickness of the layer 2 on the front side was 3 mm, and the thickness of the layer 3 on the back side was 1 mm.

The molded article of Test Example 3; a back layer material C is disposed on a lower mold of a flat plate forming mold, a surface layer material B is disposed on the back layer material C, and then Lower the mold, tighten the mold,
The back surface layer material C and the surface layer material B were compression-molded in a mold, and the back surface layer material C and the surface layer material B were thermally cured and bonded. As a result, as shown in FIG. 1, a molded product having a multilayer structure in which the layer 3 on the back side is laminated on one side of the layer 2 on the front side (having a thickness of 5 m)
m), wherein the layer 2 on the front side is a layer containing a cured product of the unsaturated polyester resin but not containing the glass fiber, and the layer 3 on the back side is composed of the cured product of the unsaturated polyester resin and the fiber length 1.
A molded article containing glass fibers of inches and having a thickness fraction of the layer 2 on the front side of 80% (4 mm thickness) and a thickness fraction of the layer 3 on the back side of 20% (1 mm thickness) is obtained. Was.

Molded product of Test Example 4; surface layer material A on lower mold
Alone and then compression molded. As a result, the cured product of the unsaturated polyester resin and the fiber length 1 /
A molded product having a single-layer structure (thickness: 4 mm) consisting of a single layer containing glass fibers of 8 inches and having no multilayer structure was obtained.

Molded product of Test Example 5; surface layer material A on lower mold
Alone and then compression molded. However, the amount of the surface layer material A was twice the amount of Test Example 4. As a result, a molded product having the same single-layer structure as in Test Example 4 was obtained except that the thickness of the molded product was 8 mm.

The ball impact strength of the molded products of Test Examples 1 to 5 was measured. Measurement conditions: A steel ball weighing 1 kg was dropped onto the surface formed by the upper mold (the surface of the layer 2 on the front side) at different heights, and the height of the dropped ball and the occurrence of cracks in the molded product were measured. did. Table 2 shows the measurement results of the falling ball impact strength together with the configuration of the molded product and the compression molding conditions.

[0033]

[Table 2]

Comparing the falling ball impact strengths of the molded products of Test Example 1 and Test Example 5, the total thickness of both molded products was 8 mm.
Despite that, in the case of the molded article of Test Example 1, no crack was generated by the falling ball impact having a falling ball height of 100 cm, but the molded article having the single-layer structure of Test Example 5 had a falling ball height of 100c.
The crack occurred at m. This means that the layer 3 (thickness 2) formed by the back layer material C containing glass fiber having a fiber length of 1 inch.
mm) contributed to the excellent impact resistance of Test Example 1.

Comparing the falling ball impact strengths of the molded products of Test Example 2 and Test Example 4, the total thickness of the molded products was 4 mm.
Despite this, in the case of the molded product having the multilayer structure of Test Example 2, no crack was generated by the falling ball impact of 80 cm, but the molded product having the single layer structure of Test Example 4 was cracked at 40 cm. . That is, the layer 3 (at a thickness of 1 mm) formed of the back layer material C containing glass fiber having a fiber length of 1 inch contributed to the excellent impact strength of Test Example 2.

Test Example 2 (Thickness 4 mm, weight 1.8 kg)
Comparing the ball impact strengths of the molded articles of Example 5 and Test Example 5 (thickness: 8 mm, weight: 3.6 kg), it is found that Test Example 2 and Test Example 5 have approximately the same ball impact strength. In other words, in terms of strength, it can be said that the molded product having the multilayer structure of Test Example 2 is a molded product that is reduced in thickness by half and reduced in weight as compared with the molded product having the single layer structure of Test Example 5. This means that the 1 mm thick layer (including 1 inch long glass fiber) formed by the back layer material C is comparable in strength to a 5 mm thick layer containing 1/8 inch long glass fiber. It indicates that you want to.

The molded article of Test Example 3 (total thickness 5 mm
And the weight was 2.25 kg), and the ball had a falling ball impact strength similar to that of Test Example 5 (8 mm in thickness and 3.6 kg in weight). By the way, the configuration of the molded article having a multilayer structure of Test Example 3 is such that a layer having a thickness of 4 mm, which does not contain glass fibers, is used as the front layer 2 and a glass fiber having a fiber length of 1 inch is provided on the back surface of the front layer 2. (A glass fiber content of 2 mm)
5%) as a layer 3 on the back side. As described above, if a layer containing glass fiber having a fiber length of 1 inch is laminated on the back surface of a layer containing no glass fiber, a molded article having a single-layer structure including glass fiber having a fiber length of 1/8 inch (for example, It can be seen that the thickness of the molded product can be made thinner and lighter than that of the molded product of Test Example 5).

Since the surface layer of the molded article of Test Example 3 was a dense layer containing no glass fiber, it was superior in surface smoothness and appearance in comparison with the molded article of Test Example 5. Texture was obtained. In addition, what used the system which does not contain glass fiber for the surface layer is excellent in repairability (post-processability). On the other hand, in the case where a system containing glass fibers is used for the surface layer, if the outermost surface is shaved off by sanding, the glass fibers are exposed, so that the surface cannot have gloss again. By the way, the surface layer material A, the surface layer material B, and the back layer material C
Among them, the back layer material C (so-called SMC) has the lowest material cost, and the surface layer material A and the surface layer material B (BM
C) is almost equivalent. Therefore, when comparing the material costs of Test Example 5 and Test Example 3, since Test Example 3 uses the back surface layer material C, the material cost can be lower than in the case of Test Example 5.

[0039]

As described above, the fiber-reinforced resin molded article of the present invention is excellent in strength such as impact resistance, surface smoothness, etc., and can achieve weight reduction and reduction in manufacturing cost, and high quality. It is. Further, according to the production method of the present invention, the fiber-reinforced resin molded article can be easily produced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a fiber-reinforced resin molded product according to the present invention.

[Explanation of symbols]

1 ... fiber-reinforced resin molded product (molded product), 2 ... surface side layer,
3 ... Backside layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) E04C 2/22 E04C 2/22 // B29K 101: 10 B29K 101: 10 105: 06 105: 06 F-term ( Reference) 2E162 CD04 CD05 4F072 AA02 AA07 AB09 AB14 AB34 AD09 AD38 AK03 AK05 AK14 AL06 AL17 4F100 AA08 AA19 AG00 AK01A AK44 BA02 BA41 CA02 CA30 DG03A DG03B EJ42 EJ422 GB08 JB12A JB12 AD03 AB03 AD03 FB11 FB22 FF01 FF05

Claims (4)

[Claims] 1. A fiber-reinforced resin molded product comprising a thermosetting resin and a reinforcing fiber, wherein the fiber length of the reinforcing fiber is longer on the back side than on the front side. 2. A layer containing a thermosetting resin and a reinforcing fiber having a fiber length of 10 to 30 mm is formed on one side of a layer containing a thermosetting resin and a reinforcing fiber having a fiber length of 2 to 6.5 mm. A fiber-reinforced resin molded product. 3. A thermosetting resin and a fiber length of 10 to 3 on one side of a layer containing a thermosetting resin and containing substantially no reinforcing fibers.
A fiber-reinforced resin molded product, wherein a layer containing a reinforcing fiber of 0 mm is formed. 4. A molding material or a thermosetting resin containing a thermosetting resin and containing substantially no reinforcing fibers, and a fiber length of 2 to 6.5.
mm molding material containing reinforcing fibers, and a molding material containing a thermosetting resin and a reinforcing fiber having a fiber length of 10 to 30 mm,
A method for producing a fiber-reinforced resin molded product, which is arranged in a molding die and compression-molded.