JPH0885112A - Press molding material and production thereof - Google Patents

Abstract

PURPOSE: To obtain a press molding material which can be molded at a low pressure and has an excellent handling workability. CONSTITUTION: A press molding material is made of granules mainly composed of a semi-cured fiber-reinforced polyester resin in an almost cylindrical form of a size ranging 5-50mm in length and 0.5-10mm in diameter. Since the press molding material is not sticky and can flow without requiring a high clamping force, it can be molded at a low pressure into a molded piece of a large size and a complicated shape using a relatively small-sized equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-molding material which is excellent in handling workability and can be press-molded at a relatively low pressure, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, SMC has been used as a press molding material.
(Sheet molding compound) and TMC (thick molding c
(Ompound), a glass sheet or other fibrous material is impregnated with a resin liquid containing uncured unsaturated polyester resin as the main material, and then both surfaces are covered with polyethylene film, etc., and aged sheet-shaped press molding materials are known. Has been.

Further, there is also known a press molding material such as BMC (bulk molding compound) obtained by kneading the above resin composition with a kneader or the like to form a lump (for example, published by Nikkan Kogyo Shimbun). "Polyester Resin Handbook", 1988 edition, pp. 645-648).

Since these sheet-shaped or lump-shaped press molding materials are extremely sticky as they are, thickening agents such as magnesium oxide and magnesium hydroxide are usually added. Therefore, such a molding material has a high viscosity, and during press molding, a high molding pressure is required when compressing the molding material charged between the molds, and the equipment must be enlarged. There was a problem. Even if it is not so, the size of the molded product is becoming larger and the shape is becoming more complicated due to the market needs. Even if it is a small molding machine and the molded product has a complicated shape. The advent of molding materials capable of low-pressure molding has been strongly demanded.

Therefore, a press-molding material which is non-greasy and can be molded at a relatively low pressure has been developed. For example, JP-A-55-82115 discloses a resin containing an unsaturated fatty acid or an oil-modified unsaturated polyester having an acid value in a specific range, a thermoplastic resin, and a monomer copolymerizable therewith. Compositions are disclosed.

[0006]

However, the prior art described in the above publication is to improve the flow characteristics by lowering the initial flow viscosity at the time of molding, thereby enabling molding at low pressure. In view of this, the fluidity of the molding material is expressed by the compression force of the press, and in this respect, there is no difference from the conventional technique, and there is a limit to the reduction of the press molding pressure.

The present invention eliminates the above-mentioned drawbacks of the prior art, enables molding at a lower pressure, has good handling workability, and requires a resin based on a special formulation as in the above prior art. First, the present invention has been made for the purpose of providing a press-molding material having a low manufacturing cost and a manufacturing method thereof.

[0008]

According to the first aspect of the present invention,
"A semi-cured fiber-reinforced unsaturated polyester resin is used as the main material, and the size of one grain is 5 to 50 mm in length and 0.5 in diameter.
It is a press-molding material characterized by comprising a granular material having a substantially columnar shape in the range of 10 mm to 10 mm, which achieves one of the above objects.

According to a second aspect of the present invention, "a resin liquid containing an uncured unsaturated polyester resin as a main material containing a low temperature side curing agent (A) and a high temperature side curing agent (B) while paying out continuous fibers. By using a curing mold having a cylindrical inner wall surface capable of being shaped into a predetermined outer diameter by impregnating the above with a radical of the high temperature side curing agent (B) which is higher than the radical generation temperature of the low temperature side curing agent (A). It is a method for producing a press-molding material, which comprises heating and semi-curing under a temperature condition lower than the generation temperature, and then cutting the granules into short pieces, whereby another purpose described above is obtained. To be achieved.

As the reinforcing fiber used in the present invention, a fiber which is stable to the heat energy received at the time of production or use of the molding material mainly composed of the unsaturated polyester resin used is used. For example, glass fiber, carbon fiber, silicon / titanium / carbon fiber, boron fiber, fine metal fiber, aramid fiber, econol fiber,
Organic fibers such as polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers and vinylon fibers may be mentioned.

The reinforcing fiber has a diameter of 1
A so-called continuous fiber is used in which a large number of monofilaments having a size of up to 50 μm are bundled to form a strand, and the strand is uniformly aligned and roving so as to have a predetermined count. If the diameter of the monofilament at this time is less than 1 μm, it may be difficult to impregnate each fiber with the matrix resin, and if it exceeds 50 μm, fiber breakage tends to be remarkable.

In the present invention, the ratio of the matrix resin and the reinforcing fiber is appropriately determined depending on the required physical properties of the fiber-reinforced resin molded product obtained by press molding, but usually 100 parts by weight of the resin is used. 50 reinforcing fibers
The proportion is preferably about 500 parts by weight. If the amount of the reinforcing fibers is less than 50 parts by weight, the mechanical strength of the fiber-reinforced resin molded product may not be sufficient, and if it exceeds 500 parts by weight, it becomes difficult to uniformly disperse the reinforcing fibers in the matrix resin, resulting in voids. The strength may be extremely reduced due to the occurrence of such as.

The unsaturated polyester resin referred to in the present invention does not refer to a specific one, but is a general-purpose unsaturated polyester resin itself. That is, unsaturated polybasic acids, polybasic acids such as saturated polybasic acids and various glycols are polycondensed as raw materials, and these are dissolved in copolymerizable monomers such as styrene to obtain uncured unsaturated polyester. It is a resin. Copolymerize and crosslink in the presence of heat or curing agents.

Specific examples of the unsaturated polybasic acid include maleic anhydride, fumaric acid, itaconic acid and citraconic acid. Specific examples of the saturated polybasic acid include phthalic anhydride, isophthalic acid and terephthalic acid. , Tetrahydrophthalic anhydride, adipic acid, sebacic acid and the like.

Specific examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3 butanediol, 1,4 butanediol,
1,6 hexanediol, hydrogenated bisphenol A, bisphenol A propyleneoxy adduct, dibromoneopentyl glycol, pentaerythritol diallyl ether, allyl glycidyl ether and the like can be mentioned.

Specific examples of the copolymerizable monomers include styrene, vinyltoluene, α-methylstyrene, methyl methacrylate, vinyl acetate, diallyl phthalate, diallyl isophthalate, triallyl isocyanate, diallyl tetrabromophthalate and phenoxyethyl acrylate. 1,6 hexanediol diacrylate, trimethylolpropane acrylate, 2-hydroxyethyl acrylate and the like are used. The proportion of the copolymerizable monomers used with respect to the unsaturated polyester resin is usually 20.
-60% by weight.

The unsaturated polyester resin used in the present invention includes, in addition to the reinforcing fiber and the curing agent, additives such as a stabilizer, a lubricant, a processing aid, a plasticizer and a colorant, if necessary.
In addition, fillers such as calcium carbonate and metal oxides are mixed.

The molding material according to the first aspect of the present invention comprises a fiber-reinforced unsaturated polyester resin, which is hardened by a hardening agent and, if necessary, a thickening agent, as a main material, and is in a specific size range. It is the body. In this state, the matrix resin is almost cured and, so to speak, pelletized. This point is a big difference from the conventional press molding material, because it is non-sticky, it is extremely easy to insert it into the mold of the press machine, and even without relying on mechanical high pressure, It can be uniformly dispersed and charged between the molds.

This molding material is limited in the shape and size of each grain, and has a length of 5 to 50 mm and a diameter of 0.5 to 10.
It should have a substantially cylindrical shape of mm. By adopting this shape and size, improvement of handling workability,
Low-pressure molding becomes possible. If the size is smaller than this size, the reinforcing fiber is inevitably short and the strength is lowered, and if the size is larger, the handleability is deteriorated.

The method for producing the molding material according to the second aspect of the present invention is the most effective method for obtaining the molding material according to the first aspect from the uncured unsaturated polyester resin. That is, two types of curing agents, a low temperature side curing agent (A) and a high temperature side curing agent (B), where both radical generation temperatures are different by 20 ° C. or more, are blended with an uncured unsaturated polyester resin, When the continuous fiber is impregnated with the resin and heated under a temperature condition that is equal to or higher than the radical generation temperature of the low temperature side curing agent (A) and is lower than the high temperature side curing agent (B) radical generation temperature, the semi-cured fiber reinforced Saturated polyester resin can be obtained in-line at high speed.

In this heating / semi-curing, the uncured unsaturated polyester resin-impregnated continuous fiber is formed into a cylindrical inner wall surface having a predetermined outer diameter, that is, an outer diameter of 0.5 to 10 mm. A temperature higher than the radical generation temperature of the low temperature side curing agent (A) and lower than the radical generation temperature of the high temperature side curing agent (B). It is set under the conditions.

Further, in the unsaturated polyester resin in the semi-cured state, it is preferable that the ratio of the polymerizable monomer to be polymerized by polymerization is in the range of 0.01 to 45%, and less than 0.01%. When it is, it remains substantially liquid and does not have a semi-cured effect, and when it exceeds 45%, it becomes too hard and it may be difficult to shape the final molded product.

By the way, as the curing agent (A) or (B), various peroxides are adopted as will be described later.
It is preferable that both radical generation temperatures differ by 20 ° C. or more. Incidentally, the low temperature side curing agent (A),
Alternatively, the radical generation temperature in the high temperature side curing agent (B) refers to the temperature at which the half-life is 10 hours or less (hereinafter referred to as “10-hour half-life temperature”).

When the radical generation temperature of both is different by 20 ° C. or more, but the combination of the low temperature side curing agent (A) and the high temperature side curing agent (B) is not a combination, that is, when the difference in radical generation temperature is less than 20 ° C. , The temperature adjustment for semi-curing is delicate, and when the low temperature side curing agent (A) is decomposed, the high temperature side curing agent (B) is considerably decomposed, and a book that uses a plurality of different types of curing agents. The effect based on the means unique to the invention is reduced.

With respect to the amount of the curing agent, the low temperature side curing agent (A) is preferably 0.03 to 2 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. If the amount exceeds 2 parts by weight, the amount of the curing agent is large, and only the low temperature side curing agent (A) is used for final curing. If the amount is less than 0.03 parts by weight, the time required to reach a semi-cured state. It takes too much time, which makes manufacturing difficult.

The 10-hour half-life temperature of the curing agent used is preferably in the range of 20 to 190 ° C. on both the low temperature side and the high temperature side. If the temperature is less than 20 ° C., a storage and a manufacturing device equipped with a special cooling device are required, and further abnormal reaction is likely to occur, which makes the production extremely dangerous. Further, when the temperature exceeds 190 ° C, a high temperature is required to generate radicals, which is economically disadvantageous, and in addition, the polymerizable monomer in the resin is volatilized to cause voids or cracks in the molded body. Occurs and the molding performance deteriorates.

Therefore, both the low temperature side curing agent (A) and the high temperature side curing agent (B) have a 10-hour half-life temperature of 20 to 1 for the curing agent.
When the combination of those within the range of 90 ° C is selected, that of the low temperature side curing agent (A) is selected from 20 to 170 ° C, and that of the high temperature side curing agent (B) is selected from 40 to 190 ° C. Become.

Examples of combinations of such curing agents are listed below. The number in parentheses is the 10-hour half-life temperature (° C). (1) (A) t-Butylperoxy (2-ethylhexanoate) (72.5) (B) t-Butylperoxybenzoate (104) (2) (A) Benzoyl peroxide (74) (B ) Dicumyl peroxide (117) (3) (A) t-butyl peroxyisopropyl carbonate (97) (B) Di-t-butyl peroxide (126) (4) (A) Methyl ethyl ketone peroxide (105) ( B) t-butyl hydroperoxide (171) (5) (A) cyclohexanone peroxide (90) (B) diisopropylbenzene hydroperoxide (150) (6) (A) 2,2-bis (4,4-) Di-t-butylperoxycyclohexyl) propane (92) (B) t-butylcumyl peroxide (121) (7) (A) t-bu Ruperoxypivalate (56) (B) 2,2-di- (t-butylperoxy) butane (102) (8) (A) Methyl isobutyl ketone peroxide (88) (B) 2,4,4- Thimethylpentyl-2-hydroperoxide (135) (9) (A) Methylcyclohexanone peroxide (96) (B) Acetylacetone peroxide (130) (10) (A) p-Cyclobenzoyl peroxide (75) ( B) Tris- (t-butylperoxy) triazine (110)

Next, the method for producing the molding material according to the second aspect of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic explanatory view showing an example of an apparatus for carrying out the method for producing a molding material according to the second aspect of the invention. In FIG. 1, only 6 bundles of continuous fibers F are shown for convenience, but a larger number of bundles may be used as needed.

In FIG. 1, 1, 1 ... Are bobbins of continuous fibers F and 2 are filled with uncured unsaturated polyester resin liquid a (containing low temperature side curing agent (A) and high temperature side curing agent (B)). The impregnated tanks 3, 3 and 3 are aligners, 4, 4, ... Are dippers, and the uncured unsaturated polyester resin impregnated tank 2
Is a guide roll or guide rod for guiding and taking out the continuous fiber F.

Reference numeral 5 is an infeed, and 6 is a curing mold. The continuous fiber F impregnated with an uncured unsaturated polyester resin is heated to a temperature not lower than the decomposition temperature of the low temperature side curing agent (A),
This is for heating in a temperature range below the decomposition temperature of the high temperature side curing agent (B) to semi-cure, and for continuously withdrawing a molded body having a substantially circular cross section. A plurality of material passages whose outer diameters are regulated are provided so as to extend in parallel. 7 is a take-up roll, 8
Is a cutter (pelletizer) capable of continuously cutting a semi-cured molded body into a length of 5 to 50 mm.

In order to carry out the invention of claim 2 by using the above-mentioned device, the bobbin 1,
While feeding the continuous fibers F from 1 ..., the continuous fibers F are sequentially arranged through the aligning tools 3 and 3. Then, it is dipped in the uncured unsaturated polyester resin impregnation tank 2 along the dipper 4, and when it is passed, the material is further adjusted by the infeed 5 and introduced into the curing mold 6. In the curing mold 6, the matrix resin is heated to a predetermined temperature and shaped into a semi-cured long rod having a thin round bar shape. Then, after passing through the take-up roll 7, the cutter 8 cuts to a length of 5 to 50 mm to obtain the molding material 9 of the present invention. In this example, the uncured unsaturated polyester resin was impregnated before introducing the continuous fiber F into the curing mold 6, but the continuous fiber F was injected and impregnated in the curing mold. May be.

To perform press molding using the molding material of the invention of claim 1, the molding material is charged into a molding machine heated to a temperature higher than the radical generation temperature of the high temperature side curing agent (B), and is heated and activated. By shaping, the final molded body can be obtained. In this case, an ordinary press machine can be used as it is, but if possible, it is preferable to use a machine that can open the mold clamping mold in the horizontal direction as shown in FIGS. 2 shows a mold clamping state, and FIG. 3 is a sectional view showing a half mold clamping state.

In FIGS. 2 and 3, a reference numeral 10 designates a press mold which can be opened in the horizontal direction.
A fixed die 12 and a hydraulic cylinder 13 for opening and closing the movable die 11 with respect to the fixed die 12. Also,
Reference numeral 14 is a shear edge portion formed by both the movable die 11 and the fixed die 12.

As described above, in particular, when a mold capable of opening the mold clamping mold in the horizontal direction is used, the molding material charging space (which may be smaller than that in the case of using the conventional molding material) is formed in the vertical direction, and the granular shape is formed. This is because the molding material composed of the body can be quickly and densely filled by utilizing its gravity. However, even the most widely used mold that can open and close the mold in the vertical direction can be used.

It is preferable that the molding material is charged in a half tightened state. In this half-tightened state, the movable die 11 is the fixed die 12
On the other hand, during the operation in the mold clamping direction, it refers to the state from the moment when the shear edge portion 14 is engaged (in the case of FIG. 3) to the complete mold clamping (in the case of FIG. 2). The mold opening distance d from the half-closed state to the completely closed state is preferably 1 to 20 times the length of the molding material used. When it is less than 1, charging of the molding material becomes difficult, and when it exceeds 20 times, the molding material may be unevenly distributed downward.

Then, a required amount of the molding material is dropped into the space between the molds thus semi-tightened. At this time, when it is difficult to drop, a method of vibrating the mold, a method of charging with the help of fluid pressure such as air, a method of ejecting a material between the molds using a nozzle, etc. are appropriately adopted. Good. in this case,
The time required for dropping is preferably as short as possible from the viewpoint of productivity, and the time required for one batch is preferably adjusted to 20 minutes or less. If it exceeds 20 minutes, the mold is heated to the decomposition temperature of the high temperature side curing agent (B) or higher,
There is a case where the molding material is partially hardened, which makes it difficult to perform press molding by uniform mold clamping. In the case of a mold capable of opening and closing the mold in the vertical direction, a method of charging by fluid pressure such as air, a method of spraying a material between the molds using a nozzle, or the like may be adopted.

In this way, the molding die 10 charged with the material is pressed by the compression operation of the cylinder 13 to a completely clamped state, and the molding material is heated and compressed to form the finally shaped molding. Get the body. A vacuum may be drawn between the molds to prevent the generation of voids and the like.

[0040]

The press-molding material according to the first aspect of the present invention is a pellet mainly composed of a semi-cured fiber-reinforced unsaturated polyester resin, so that it is non-greasy, has excellent handling workability, and is sprayed. Since it is possible to uniformly disperse and charge between the molds by a simple means such as dropping, low-pressure molding can be performed at the time of shaping the final molded body.

In the method for producing a press-molding material according to the second aspect of the present invention, continuous fibers are impregnated with an uncured unsaturated polyester resin containing a low temperature side curing agent (A) and a high temperature side curing agent (B). Since a method of shaping the material into a predetermined shape by the pultrusion method using this as a material, the molding material of the invention according to claim 1 can be easily and efficiently produced by using the pultrusion molding equipment and molding technology which are general-purpose techniques. Can be manufactured in a simple manner.

Further, the press-molding material of the invention according to claim 1 is produced by containing a low-temperature side curing agent (A) and a high-temperature side curing agent (B), and utilizing the difference in radical generation temperature between them.
In addition, it is possible to obtain a molding material that can surely shape the final molded body.

[0043]

EXAMPLES Examples of the present invention will be described in detail below.

(Example 1) As an uncured unsaturated polyester resin, a copolymer consisting of three components of maleic anhydride, neopentyl glycol and phthalic anhydride was added so that styrene was 40% by weight based on the whole. In the adjusted liquid resin, 1 part by weight of t-butylperoxybenzoate (10-hour half-life temperature = 104 ° C.), and low temperature side curing agent (A) as 100 parts by weight of the resin as the high temperature side curing agent (B)
As the resin composition, 0.7 part by weight of t-butylperoxy (2-ethylhexanoate) (10-hour half-life temperature = 72.5 ° C.) was added.

As continuous fiber F, 4450 tex of GF
Using 30 bundles of continuous fibers made of roving, the molding material of the invention of claim 1 was manufactured by the manufacturing method of the invention of claim 2 shown in FIG. Curing die set temperature = 8
7 ° C, the cross-sectional shape and dimensions of the material passage are round holes with an inner diameter of 4 mmφ, the resin weight ratio immediately after passing through the curing mold = 40%
The dimensions of the obtained molding material are as follows: length = 12 mm, outer diameter =
It was 3.8 mm.

Regarding the semi-cured molding material cut so that the maximum diameter is at least 1 mm or less,
The amount of the reaction monomer was 15% as a result of measuring the amount of extraction after immersing in excess methylene chloride under the temperature condition of 30 ° C. for 48 hours.

Next, using the molding material obtained as described above, a fiber-reinforced resin molded body as a final molded body was manufactured. As the device, the device shown in FIGS. 2 and 3 was used. Mold set temperature = 130 ° C, mold opening distance (d) = 1
05 mm, charging method of molding material = free fall, time required for charging = about 35 seconds, mold clamping force = 150 t.

(Comparative Example 1) The same liquid resin as used in Example 1 was used, and the same high temperature side curing agent (B) used in Example 1 was used as a curing agent for 100 parts by weight of the resin. Was blended in the same proportion, and a resin composition containing 1 part by weight of magnesium oxide as a thickening agent was used.

As the reinforcing fiber, a chopped strand mat having a length of 12 mm was used, and the resin composition was impregnated so that the weight ratio of the resin composition was 40% by weight, and then the ambient temperature was set to 40 ° C. The material maintained for 38 hours was used as the molding material. (SMC)

Then, the movable mold and the fixed mold shown in FIG. 4 were attached to a normal press molding machine capable of opening the mold clamping mold in the vertical direction, and press molding was carried out by setting the mold temperature to 130 ° C.
The mold clamping force required at this time was about 670 t.

Example 2 The same molding material as in Example 1 was used, except that the molding material used had a length of 19 mm and an outer diameter of 4 mmφ. The amount of the reaction monomer in the extraction test of the semi-cured product was 15%.

Next, a fiber-reinforced resin molded body was manufactured in the same manner as in Example 1 except that the die distance (d) was set to 75 mm. Incidentally, the time required for charging the molding material = about 20 seconds,
The mold clamping force was about 260 t.

Comparative Example 2 The same molding material and molding apparatus as those used in Comparative Example 1 were used, and the molding material was intensively charged in the center of the fixed mold (lower mold). (S
MC) The mold clamping force required at this time was about 1150 t.

[0054]

The press-molding material according to the first aspect of the present invention is excellent in handling workability because it is not sticky, and the production efficiency of the fiber-reinforced resin molding is improved. Also, since the molding material can be pre-arranged by means other than the mold clamping force, the mold clamping force, which has the largest proportion of the molding pressure, does not require a high mold clamping force for the resin flow, and the overall molding pressure can be greatly reduced. The equipment can be downsized, and complex moldings can be molded by a small machine, which in turn can reduce equipment costs and manufacturing costs.

The method for producing a press-molding material according to the second aspect of the present invention comprises a low temperature side curing agent (A) and a high temperature side curing agent (B), and utilizes the difference in radical generation temperature between the two to produce a press molding material. It is possible to manufacture the press-molding material of the invention according to item 1, and obtain a molding material that can surely shape the final molded body. Further, the general-purpose technique for pultrusion molding and the molding technique can be adopted as they are without the need for special manufacturing facilities, and the production suitable for use in the production of the molding material of the invention according to claim 1. Is the way.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an example of an apparatus for carrying out the method for producing a molding material according to the second aspect of the invention.

FIG. 2 is a drawing showing only a main part of a molding machine used when press-molding a fiber-reinforced resin molded product using the molding material of the invention of claim 1, and showing a mold clamping state. It is sectional drawing shown.

FIG. 3 is a cross-sectional view showing a mold half-clamped state of the above mold.

[Explanation of symbols]

 F Continuous fiber a Uncured unsaturated polyester resin liquid 2 Impregnation tank 6 Curing mold 7 Take-up roll 8 Cutter 9 Molding material

Claims (2)

[Claims] 1. A semi-cured fiber-reinforced unsaturated polyester resin as a main material, and the size of each grain is 5 to 50 m in length.
A press-molding material comprising a granular material having a substantially cylindrical shape and having a diameter of m and a diameter of 0.5 to 10 mm. 2. A continuous liquid is fed out and impregnated with a resin liquid containing an uncured unsaturated polyester resin containing a low temperature side curing agent (A) and a high temperature side curing agent (B) as a main material, and a predetermined amount Using a curing mold having a cylindrical inner wall surface that can be shaped into a diameter, a temperature condition that is equal to or higher than the radical generation temperature of the low temperature side curing agent (A) and lower than the radical generation temperature of the high temperature side curing agent (B). A method for producing a press-molding material, which comprises heating and semi-curing at 2, and then cutting the material into short pieces to obtain granules.