JP2013018858A - Premolded body, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a premolded body, capable of controlling so that a sufficiently high adhesive strength can easily be acquired between a resin supplied for insert molding of a matrix resin of the premolded body and only a joining portion of the premolded body with the supplied resin; and to provide a premolded body manufactured by the method.SOLUTION: A fiber-reinforced resin A including a matrix resin which is a crystalline thermoplastic resin is made a premolded body. The method is for manufacturing the premolded body for insert molding the fiber-reinforced resin A by supplying a liquefied resin B. At least a part of a joining surface of the fiber-reinforced resin A with the resin B is controlled in the range of a crystallinity degree of 5 to 15%, for example, by quenching. The molded body is manufactured by the method.

Description

  The present invention relates to a preform made of a fiber-reinforced resin for insert molding of a preform by supplying a resin, and a method for manufacturing the preform, and in particular, can improve the adhesiveness with the supplied resin and improve the moldability. The present invention relates to a method for manufacturing a preform, and a preform manufactured by the method.

  A method of insert molding a composite molded body by supplying a molten resin around a preformed fiber reinforced resin preform is well known. For example, as shown in FIG. 2, the preform used for such insert molding is usually impregnated with a resin 102 as a matrix in a reinforcing fiber 101 (for example, a reinforcing fiber arranged in parallel in one direction). It consists of a preform or a prepreg preform 100. Such a preform 100 is placed in a mold, for example, and a molten resin is supplied around it by injection, for example, to perform insert molding, and the preform 100 and the supply resin are integrated. Like to get.

  However, in insert molding using the preform 100 as described above, particularly when the matrix resin 102 constituting the preform 100 and the resin supplied to the periphery thereof are different, the adhesiveness at the interface between them is different. It becomes a problem. That is, if the adhesiveness at the interface is low, the preform may be peeled off during molding, or the molded composite material as a whole cannot exhibit desired mechanical properties (strength, elastic modulus). Further, if peeling or deviation occurs at the interface during molding, the moldability is significantly impaired.

  Patent Document 1 exemplifies a method in which a reinforcing material as a preform formed of reinforcing fibers and a fiber reinforced resin of a binder is placed in a mold, and a resin is supplied to insert-mold a composite molded body. However, even in the method disclosed in Patent Document 1, basically different resins are used for the matrix resin of the preform and the resin supplied for insert molding, and these resins are directly bonded. Depending on the combination of the resins, a sufficiently high adhesive strength between the two resins may not be achieved, and a sufficiently high reinforcing effect on the entire composite molded body by the preform may not be obtained. Further, if the adhesiveness is insufficient, good moldability cannot be obtained as described above.

  In order to improve the adhesion between the matrix resin of the preform and the resin supplied to the surroundings, another resin layer having a high adhesiveness to the resin supplied to the surroundings is provided in advance on the surface of the preform. However, there is an increase in the number of steps for providing the other resin layer, resulting in a decrease in productivity, and a new need to consider the bondability between the other resin layer and the matrix resin of the preform. If the bondability is low, eventually, the same problems as peeling and misalignment as described above, and the problem of deterioration of moldability will occur. Therefore, ideally, it is desired to use only one type of matrix resin for the preform and to improve the adhesiveness only on the joint surface with the resin supplied to the surroundings at the time of insert molding.

JP 2001-293746 A

  Accordingly, an object of the present invention is to focus on the above-mentioned problems when insert molding is performed using a preform of a fiber reinforced resin, and is bonded to a resin supplied for insert molding of a matrix resin of the preform. A method for producing a preform that can be easily controlled so that sufficiently high adhesive strength can be obtained with a supplied resin, and a preform produced by the method. It is to provide.

  In order to solve the above-mentioned problems, a method for producing a preform according to the present invention includes a fiber reinforced resin A whose matrix resin is a crystalline thermoplastic resin as a preform, and a liquefied resin B is supplied. A method for manufacturing the preform for insert molding the fiber reinforced resin A, wherein at least a part of a surface of the fiber reinforced resin A to be bonded to the resin B is in a range of 5 to 15% in crystallinity. It consists of the method characterized by controlling inside.

Here, the crystallinity will be described. The crystallinity can theoretically be defined as follows. That is, there are two types of thermoplastic resins, crystalline resins and amorphous resins, and only crystalline resins have a region in which polymer chains are arranged (oriented) with an ordered structure called “crystal”. . On the other hand, the amorphous resin does not have such a regular structure, and is in a non-oriented / random state such that lint is entangled. The degree of crystallinity is a ratio of the weight occupied by the crystalline region in the entire crystalline region and amorphous region of the resin solid, calculated as follows.
Crystallinity (%) = weight of crystalline region / (weight of crystalline region + weight of amorphous region) × 100
In the present invention, paying attention to the fact that this crystallinity has a great influence on the adhesiveness of the resin, excellent adhesiveness is realized by controlling the crystallinity within an appropriate range.

Theoretically, this crystallinity can be defined by the above formula, but in reality, it is difficult to accurately measure the weight of the crystalline region and the weight of the amorphous region. (1) X-ray diffraction method: X-ray diffraction is measured, and the crystallinity is calculated from the peak area ratio (%) derived from the crystalline structure in the total diffraction peak area observed. And (2) thermal analysis. In the present invention, since fiber reinforced resin is targeted, the crystallinity is measured by the latter thermal analysis method.
(2) Thermal analysis method Using DSC (differential scanning calorimeter), an exothermic peak caused by crystallization and an endothermic peak caused by crystal melting were measured, and peak area J (vertical axis: W [weight] × horizontal axis : Time) and the amount of sample (g), the amount of heat of fusion (J / g) was calculated, and the crystallinity was calculated by the following equation.
Crystallinity (%) = (Measured heat of fusion-calorific value associated with crystal formation) / complete crystal melting heat × 100

  In the method for producing a preform according to the present invention, it has been found that the adhesiveness with other resins can be improved by controlling the crystallinity within an appropriate range. That is, after making the matrix resin of the fiber reinforced resin A constituting the preform as a whole into one kind of crystalline thermoplastic resin (that is, without providing another resin layer or the like), the fiber reinforced resin A At least a part of the surface to be bonded to the resin B (that is, a part of the surface layer of the matrix resin to be bonded to the resin B) is controlled within the range of 5 to 15% of crystallinity. By controlling only a specific part of the surface layer to a crystallinity within a specific range even though they are the same matrix resin, the adhesiveness of only the specific part of the surface layer can be improved without causing a special interface in the matrix resin. Therefore, it becomes possible to improve the adhesiveness with the resin B in insert molding without impairing the mechanical properties of the insert molded product using this preform, and ensure excellent mechanical properties of the molded product after molding. In addition, the molding can be easily performed without any inconvenience, and the moldability is greatly improved. Moreover, since the same resin is used as the matrix resin of the fiber reinforced resin A and only the characteristic (crystallinity) of the specific part of the surface layer of the fiber reinforced resin A is changed, the preform according to the present invention is easily and It can be manufactured at low cost.

  In such a method for producing a preform according to the present invention, the crystallinity can be controlled within a desired range by a cooling rate, particularly rapid cooling. For example, after impregnating the reinforced fiber of the fiber reinforced resin A with the matrix resin, the surface layer portion is rapidly cooled to crystallize at least a part of the surface of the fiber reinforced resin A bonded to the resin B. The degree can be controlled within a range of 5 to 15%, and at least a part of the surface not bonded to the resin B can be controlled to exceed the degree of crystallinity of 15%. That is, since the crystallinity can be controlled to decrease by increasing the cooling rate, the specific surface layer portion is rapidly cooled to control the crystallinity within a range of 5 to 15%, and at least the surface not bonded to the resin B For a part (that is, for a part that does not require high adhesiveness with the resin B), the crystallinity is controlled to exceed 15% without increasing the cooling rate. By such control, it is possible to reliably improve the adhesiveness with the resin B only at a necessary portion, and simply ensure desired mechanical properties for a portion that does not require an improvement in adhesiveness. .

  In the method for producing a preform according to the present invention, the form of the fiber reinforced resin A is not particularly limited, but is a preform for insert molding, controlling the crystallinity of a specific surface layer part, In particular, considering that the specific surface layer portion is rapidly cooled to control the crystallinity within a specific range, the fiber reinforced resin A is preferably formed of a plate-shaped or sheet-shaped molded body or prepreg.

  Further, the matrix resin of the fiber reinforced resin A is not particularly limited as long as at least a part of the surface to be bonded to the resin B of the fiber reinforced resin A can be controlled within a range of 5 to 15% of crystallinity. Polypropylene, polyethylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyetheretherketone, etc., which are thermoplastic resins, can be used, but the crystallinity is more reliably controlled within this specific range. In order to exhibit good adhesiveness, the main component of the matrix resin of the fiber reinforced resin A is preferably made of a high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more. Here, the main component refers to a resin composition containing 50 wt% or more of high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more. For example, in addition to other polymers and elastomers, antioxidants and heat stabilizers Plasticizers, lubricants, colorants, compatibilizers, fillers, and the like can also be blended. Of course, the high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more may be 100 wt%.

  The matrix resin on at least a part of the surface of the fiber reinforced resin A bonded to the resin B is a high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more and a cyclic polyphenylene sulfide represented by the following general formula (1) And a polyphenylene sulfide resin composition. The polyphenylene sulfide resin composition preferably contains 1 to 40 wt% of cyclic polyphenylene sulfide. More preferably, it is 4-30 wt%, More preferably, it exists in the range of 7-20 wt%. By blending such cyclic polyphenylene sulfide within the above range, the crystallinity can be more easily controlled within the range of 5 to 15%.

  Different matrix resin compositions are applied to the matrix resin on at least a part of the surface of the fiber reinforced resin A bonded to the resin B and the matrix resin on at least a part of the surface not bonded to the resin B. Is preferred. For example, when polyphenylene sulfide is applied, the polyphenylene sulfide resin composition of the high molecular weight polyphenylene sulfide and the cyclic polyphenylene sulfide described above is unevenly distributed on at least a part of the surface of the fiber reinforced resin A to be bonded to the resin B. On the other hand, it is a preferable embodiment that the high molecular weight polyphenylene sulfide is arranged so as to be unevenly distributed on at least a part of the surface of the fiber reinforced resin A that is not joined to the resin B. By controlling the degree of crystallinity within a specific range and improving the adhesiveness in insert molding, and controlling the shrinkage without deteriorating the mechanical properties, the above-described aspect allows the appearance quality and environmental resistance to be controlled. A composite material having excellent characteristics can be obtained.

  Further, the form of the reinforcing fiber of the fiber reinforced resin A is not particularly limited, but considering that the preform plays a role of a reinforcing material in insert molding, the fiber reinforced resin A is a reinforced fiber having a fiber length of 1 mm or more. It is preferable to consist of a fiber reinforced resin containing. Further, when the reinforcing fibers of the fiber reinforced resin A are oriented in one direction, the molded product can be efficiently reinforced in a specific direction to express high mechanical strength. Particularly preferred. However, other forms such as a reinforced fiber fabric can be used.

  Further, the type of the reinforcing fiber of the fiber reinforced resin A is not particularly limited, and carbon fiber, glass fiber, aramid fiber, or a mixed form of reinforcing fiber in combination of any of these can be applied. High mechanical properties (strength, elastic modulus) can be easily obtained when the structure includes carbon fibers.

  In addition, the liquefied (particularly melted) resin B supplied for insert molding can be easily molded, and can also be used for mass production. preferable.

  The type of the resin B is not particularly limited as long as it can be insert-molded. However, when the resin B is made of a thermoplastic resin, good adhesion to the fiber reinforced resin A using a crystalline thermoplastic resin as a matrix resin is obtained. In addition, the moldability in injection molding or the like is kept good.

  The resin B may be a resin alone or may contain reinforcing fibers (for example, short fiber reinforcing fibers). When the resin B contains reinforcing fibers, the mechanical strength of the entire molded product can be kept higher. The reinforcing fiber of the resin B is preferably a carbon fiber for the same reason as described above.

  The present invention also provides a preform for insert molding produced by the method as described above. Since this preform is controlled so that at least a part of the surface of the fiber reinforced resin A joined to the resin B is within a range of 5 to 15% of crystallinity, In addition to being able to exhibit excellent adhesion, the moldability can be improved, and high mechanical properties can also be realized for the obtained molded product.

  As described above, according to the preform and the manufacturing method thereof according to the present invention, the crystallinity of a specific surface layer portion of the fiber reinforced resin A constituting the preform is controlled within an appropriate range. In addition, it is possible to exhibit excellent adhesiveness to the resin B supplied at the time of insert molding, improve the moldability, and achieve high mechanical properties of the obtained molded product.

It is a schematic sectional drawing of the preforming body which concerns on one embodiment of this invention. It is a schematic sectional drawing of the conventional general preform.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic cross section of a preform 1 according to an embodiment of the present invention. In this embodiment, the preform 1 is configured as a sheet-like molded body or prepreg. The preform 1 as a whole is composed of a reinforcing fiber 2 (in this embodiment, carbon fiber, for example, carbon fiber oriented in one direction) and a matrix resin 3 (in this embodiment) made of a crystalline thermoplastic resin. , High-molecular-weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more). At least a part (upper and lower surfaces in the illustrated example) of the surface joined to the liquefied (particularly molten) resin B supplied around the fiber reinforced resin A during insert molding of the fiber reinforced resin A The low crystallinity layer 4 is controlled to have a crystallinity of 5 to 15%. Control of the crystallinity within the range of 5 to 15% is, as described above, for example, by impregnating the matrix resin 3 in the reinforcing fiber 2 of the fiber reinforced resin A and then rapidly cooling the surface layer portion. It is done by. In the illustrated example, the crystallinity of the upper and lower low crystallinity layers 4 is lower than the crystallinity of the inner layer located between them.

  When the preform 1 thus configured is placed at a predetermined position in a mold, for example, and the resin B is supplied around the mold by injection and insert molding is performed, the surface of the surface to be joined to the resin B of the fiber reinforced resin A At least a part (in the illustrated example, the upper and lower surfaces formed by the upper and lower low crystallinity layers 4) of the adhesiveness with the resin B is greatly improved. By improving the adhesiveness, the moldability in insert molding is improved, and the mechanical properties of the molded product to be molded are improved.

  The preform 1 is basically composed entirely of the fiber reinforced resin A, and only the specific surface layer portion is composed of the low crystallinity layer 4. The matrix resin 3 is used. Therefore, it is not necessary to provide the low crystallinity layer 4 as a layer of a different resin species, and the low crystallinity layer 4 can be easily and inexpensively manufactured without substantially complicating the manufacturing process of the preform 1. Furthermore, since it consists of the same matrix resin 3 as a whole, peeling does not occur inside.

  Therefore, it is possible to easily and efficiently achieve both excellent adhesiveness and moldability desired during insert molding and high mechanical properties desired for a molded article after insert molding.

  The preformed body and the manufacturing method thereof according to the present invention can be applied to any insert molding using a fiber reinforced resin A using a crystalline thermoplastic resin as a matrix resin as a preformed body. Specifically, it can be suitably used for transportation equipment such as automobiles, airplanes, ships, etc., leisure / sports members, pressure vessels, oil field excavation, and structural / quasi-structural members for civil engineering.

1 Preliminary body 2 Reinforcing fiber 3 Matrix resin 4 Low crystallinity layer

Claims (13)

  This is a method for producing the preform, in which the fiber reinforced resin A whose matrix resin is a crystalline thermoplastic resin is used as a preform, the liquefied resin B is supplied and the fiber reinforced resin A is insert-molded. Then, at least a part of the surface of the fiber reinforced resin A joined to the resin B is controlled within a range of 5 to 15% of crystallinity.   After impregnating the matrix resin into the reinforced fiber of the fiber reinforced resin A, the surface layer portion is rapidly cooled, so that at least a part of the surface of the fiber reinforced resin A bonded to the resin B has a crystallinity of 5 2. The method for producing a preform according to claim 1, wherein the preform is controlled to be within a range of ˜15%, and at least a part of the surface not bonded to the resin B is controlled to exceed a crystallinity of 15%.   The manufacturing method of the preforming body of Claim 1 or 2 with which the said fiber reinforced resin A consists of a plate-shaped or sheet-shaped molded object or a prepreg.   The method for producing a preform according to any one of claims 1 to 3, wherein a main component of the matrix resin of the fiber reinforced resin A is a high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more.   The matrix resin in at least a part of the surface joined to the resin B of the fiber reinforced resin A is composed of a resin composition of high molecular weight polyphenylene sulfide having a weight average molecular weight of 10,000 or more and cyclic polyphenylene sulfide. The manufacturing method of the preform in any one of 1-4.   The method for producing a preform according to any one of claims 1 to 5, wherein the fiber reinforced resin A is made of a fiber reinforced resin containing reinforcing fibers having a fiber length of 1 mm or more.   The method for producing a preform according to any one of claims 1 to 6, wherein the reinforcing fibers of the fiber reinforced resin A are oriented in one direction.   The manufacturing method of the preform in any one of Claims 1-7 in which the reinforced fiber of the said fiber reinforced resin A contains carbon fiber.   The method for producing a preform according to any one of claims 1 to 8, wherein the liquefied resin B is supplied into a mold by injection.   The method for producing a preform according to any one of claims 1 to 9, wherein the resin B is made of a thermoplastic resin.   The manufacturing method of the preform in any one of Claims 1-10 in which the said resin B contains a reinforced fiber.   The method for producing a preform according to claim 11, wherein the reinforcing fibers of the resin B include carbon fibers.   The preform for insert molding manufactured by the method in any one of Claims 1-12.

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