Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1999-04-09
2001-02-06
Krynski, William (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S375000, C428S378000
Reexamination Certificate
active
06183864
ABSTRACT:
The present invention relates to a thermoplastic resin-combined glass fiber base material which has good productivity and mechanical strength and is excellent in flexibility, and a process for its production.
As a molding material for a fiber reinforced thermoplastic resin (hereinafter referred to as FRTP), a prepreg for molding having a powder or fibers of a thermoplastic resin combined with continuous glass fibers, has been known. However, such a prepreg for molding is usually designed to impregnate the resin to the glass fibers when the thermoplastic resin is melt-pressed in a subsequent step, and it is usually difficult to completely impregnate the resin to the glass fibers, whereby there have been problems such that the glass content tends to be non-uniform, voids are contained in a substantial amount, and the mechanical strength is poor.
On the other hand, as FRTP whereby impregnation is relatively good, a compound having a thermoplastic resin melt-impregnated to continuous glass fibers, is known as a long fiber compound (hereinafter referred to as LFC). In LFC, a resin is preliminarily impregnated to glass fibers, whereby the resin-impregnation property during the molding is good as compared with the above described prepreg.
Further, JP-A-3-119034 discloses a string-form compound wherein the number of reinforcing fiber monofilaments is limited to improve the flexibility of conventional LFC.
However, conventional LFC has not been required to have flexibility, since it has been used usually as cut into a predetermined length to be useful as a molding material for injection molding. Accordingly, even if it has been attempted to wind up such LFC without cutting to use it as a fiber base material for various molding materials, packaging has been difficult, since the rigidity is so high that winding up is difficult, or it is hardly bent or is easily be broken. Thus, it has been difficult to apply it as a filament winding molding material or a molding material for prepreg for woven fabric or cord fabric.
Whereas, the base material disclosed in JP-A-3-119034 has good flexibility, but the number of reinforcing fiber monofilaments (the number of filaments in strand) is reduced, whereby the operation during the production tends to be cumbersome and the productivity tends to be poor, and the resulting material tends to be poor in the mechanical strength.
Namely, in a case where a glass fiber strand having a small number of filaments in strand, is to be produced, it is necessary to divide many monofilaments from one bushing into a large number of packages, whereby the operation tends to be cumbersome, and in the production of the base material, the number of filaments in strand is reduced to obtain one having a small content of reinforcing fibers, whereby the production efficiency per base material tends to be poor.
Further, the base material obtained by the above method has a small number of monofilaments and a small reinforcing effect, whereby the tensile breaking load tends to be small, and thus has had a problem that the breakage of the base material is likely to result during filament winding or processing into a woven fabric.
Under these circumstances, it is an object of the present invention to provide a thermoplastic resin-combined glass fiber base material which is useful as a filament winding molding material, a molding material for prepreg of a woven fabric or cord fabric, or LFC for injection molding, obtained by cutting such a molding material and which has good productivity and mechanical strength and is excellent in flexibility, and a process for its production.
To accomplish the above object, the present invention provides a thermoplastic resin-combined glass fiber base material, which comprises a glass fiber strand having a plurality of glass monofilaments bundled and a thermoplastic resin impregnated thereto, and which:
A) has a string form with an average diameter of from 0.2 to 1.5 mm,
B) has a glass content of from 15 to 80 vol %,
C) has an impregnation rate of the thermoplastic resin of at least 95%, and
D) satisfies R≦30D×V, where R is the radius of curvature (mm) representing the buckling limit in bending, D is the average diameter (mm), and V is the glass content (vol %/100).
Further, the present invention provides a process for producing a thermoplastic resin-combined glass fiber base material, which comprises impregnating a thermoplastic resin by a melt impregnation method to a glass fiber strand obtained by bundling a plurality of glass monofilaments without applying splitting thereto, followed by pultrusion from a nozzle and winding up, to obtain a thermoplastic resin-combined glass fiber base material having the above mentioned characteristics A to D.
The thermoplastic resin-combined glass fiber base material of the present invention has the above mentioned characteristics A to D, and thus, it is excellent in flexibility and has good handling efficiency such as good winding up efficiency, and yet it has good productivity and mechanical strength. Accordingly, it is suitable for preparation of a filament winding molding material, a molding material for prepreg of a woven fabric or cord fabric, or a molding material useful as LFC for injection molding prepared by cutting such a molding material. Further, since the impregnation rate of a thermoplastic resin is high, the glass content in the molded product can easily be made uniform, and quick molding at a low pressure can be made possible.
Further, according to the process for producing a thermoplastic resin-combined glass fiber base material of the present invention, a thermoplastic resin is impregnated to a glass fiber strand obtained by bundling without application of splitting, followed by pultrusion from a nozzle and winding up, whereby clogging of the nozzle can be prevented, and continuous production can be made possible even when the glass content is increased, and it is possible to obtain a thermoplastic resin-combined glass fiber base material which has a high impregnation rate of the thermoplastic resin, is excellent in flexibility and has little fuzz on its periphery. Further, by adjusting the number of glass monofilaments bundled to form the above glass fiber strand to be from 200 to 2,000 filaments, the flexibility can be made particularly excellent, and the production efficiency will be particularly good.
REFERENCES:
patent: 3993726 (1976-11-01), Moyer
patent: 4680224 (1987-07-01), O'Connor
patent: 4741151 (1988-05-01), Klink et al.
patent: 4802331 (1989-02-01), Klink et al.
patent: 4983453 (1991-01-01), Beall
patent: 4992229 (1991-02-01), Beever
patent: 5026410 (1991-06-01), Pollet et al.
patent: 5084305 (1992-01-01), Marttila
patent: 5409757 (1995-04-01), Muzzy et al.
patent: 6045876 (2000-04-01), Fellers et al.
patent: 0 712 716 (1996-05-01), None
patent: 3-119034 (1991-05-01), None
patent: 4-222243 (1992-08-01), None
patent: 6-23742 (1994-02-01), None
patent: 6-114830 (1994-04-01), None
Patent Abstracts of Japan, vol. 015, No. 317 (C-0858), Aug. 13, 1991, JP 03 119034, May 21, 1991.
Mizukami Toru
Ozaki Kengo
Asahi Fiber Glass Company Limited
Gray J. M.
Krynski William
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Thermoplastic resin-combined glass fiber base material and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoplastic resin-combined glass fiber base material and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic resin-combined glass fiber base material and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2612386