CS242171B1 - Polyester thermosetting composite material and its production method - Google Patents

Abstract

The invention describes a glass fiber reinforced composite material, containing in its structure a mixture of chopped glass fibers, which contains 10 to 85 % of elementary glass fibers, and 90 to 15 % of glass strands composed of 50 to 1200 elementary fibers. The composition can be prepared by impregnating a mixture of chopped fibers, of which 10 to 85 % are strands with a soluble treatment and the rest with an insoluble treatment. By thickening the composition, e.g. with magnesium oxide, a dry form of this composition is prepared, which can be cured by pressing at an elevated temperature.

Description

242171

BACKGROUND OF THE INVENTION The present invention relates to a polyester thermosetting composite reinforced with chopped glass fiber having a length of from 3 to 600 mm, and optionally from 5 to 85% by weight, comprising mainly regulating stability, theological and surface properties of the thermoset and the method of its production.

Polyester thermosetting composites have found widespread use as a construction material that continually replaces traditional materials such as wood, various coloring and alloys. In the manufacture of these compositions, glass fibers, whether in the form of tissues, mats, rovings, or chopped fibers, are used most extensively as filler (Mleziva J. et al .: Polyesters, Production and Processing thereof). SNTL Praha 2 ed. 1978) In addition to the glass fibers themselves, a wide variety of glass and carbon fiber combination compositions are known, as well as combinations and processes using glass fabrics and chopped fiber (U.S. Pat. No. 3,867,244; 3 889 035 and 3 993 828).

Pressable hardenable compositions based on unsaturated polyester resins (CS auto no. 190 815, 226 247, 226 283) are prepared by impregnation, mainly cut glass fibers, with a composition of unsaturated polyester resins which are thickened with thickeners. typically, the metal derivatives are converted to a dry, non-adhesive form and cured by elevated temperature compression according to the type of radical polymerization initiation system used. The therapeutic and technological properties of these materials are regulated by a variety of additives, usually surfactants, inhibitors, initiators, non-reinforcing fillers, pigments, dyes, separators, flame retardants, thermoplastic polymers, solvent plasticizers, and the like. The production of various products from the molding compositions thus prepared is generally carried out as follows: A separating film is removed from the prepreg, which prevents the individual layers from sticking to the coating and the equivalent amount of prepreg is cut off according to the weight of the desired product. Depending on the shape of the mold, the prepreg strip is cut into squares or tiles and placed on the bottom of the mold heated to a temperature of about 130-160 ° C after the mold is closed by the influence of temperature and pressure to melt the mold mass into all molds. the simultaneous crosslinking of matter. Depending on the weight of the product and the initiation system, the pressing time is 1 to 10 minutes. In the first phase, the molding compounds of this type have mainly found application in the manufacture of low-profile, simple larger products, in particular various covers, chair parts, such as backrests, tables and in the automotive industry for the manufacture of body parts and bumpers. Already in the development of these molding compositions, it has been found that glass fibers in the form of planar strands commonly used in the production of glass laminates by a solution-soluble solution in unsaturated poly-ester resins are prepreparable for reinforcement. When these strands are applied with the kit, it has been found that at elevated temperature and pressure during compression, the strands are broken down into. elementary fibers. When melting the mass into the entire mold part, the uniform distribution of the fibers in the mass of the product took place, which was reflected by fluctuations in the mechanical properties of the product. As a rule, in the center of the article, where the mold mass flowed into the mold part, it was at least stiffened by the fiber, as a result of which the places were brittle and almost immediately cracked. For these reasons, this technology for the production of molded glass strands, in which the constituent fibers are bonded together by the treatment of insoluble in a solution of unsaturated polyester resin, bases various polymers and polyvinyl alcohol. In applying this kind of glass strands, the above drawbacks have been eliminated, which has enabled the wide spread of these molding masses to produce products that are very laborious to produce by the technologies used in the art. With the constant pressure to replace various metal materials, especially non-ferrous metals, the molding presses, prepregs have also begun to be used in the manufacture of various molded articles, especially for the electrical industry. In the manufacture of these articles, usually of low weight and open-die-forming, edges and protrusions for the use of conventional previously used molding compositions, cracking and peeling of the product occurred, and in the treatment of the products, in particular the drilling of different holes, the solution this has been manifested by the use of various kinds of additives, predominantly thermoplastics, by the sizing of powdered fillers and additives to improve the rheological properties of the composition as prepreg modifiers.

In the study of this problem, we have found that glass-insoluble resin strands in the molding of demanding and non-resilient molded articles do not flow uniformly with the resin, but their separation occurs, which ultimately proves that the mass of the compact is unevenly crushed and fragile in places where the reinforcement is reduced. A solution to this problem is to add additives generally in combination with the treatment of the pressing technology, i.e. to increase the curing temperature and to increase the mixing time. This solution ultimately manifests itself in a reduction in production productivity. We have found that these problems are substantially eliminated using the invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester thermosetting 242171 glass-fiber-reinforced composite material having a length of 3 to 60 mm, optionally infinite in an amount of 5-85% by weight, comprising additives controlling mainly the stability, rheological and surface properties of the thermoset. The invention is based on the fact that of the total amount of glass fiber cuts it contains 10 to 85% by weight of elastic fibers and 90 to 15% by weight of glass strands composed of 50 to 1200 elemental fibers.

This material can be prepared as follows. The composition based on non-saturated polyester resins, thickened on the basis of the metal group 2 of the periodic system of elements, polymerization initiators and additives regulating the technological and utility properties of the thermoset, is applied to two release films, among which: the chopped chopped glass fiber, optionally endless, so that the chopped glass fiber is composed of a mixture containing 10 to 85% by weight of glass strands by a coating soluble in an unsaturated polyester resin solution and curing after thickening, typically by pressing at elevated temperatures.

The thickened masses can either be processed by the manufacturer himself, or distributed by various processors. The determination of the suitability of the glass fibers can be accomplished by a simple visual method, so that the dissolved strands of fiber break down into an unsaturated polyester resin solution into elemental fibers.

The principle according to the invention is based on the fact that the strands of fibers, which are generally insoluble, generally of flat shape with a width measurable in millimeters, are less flexible and mobile, forming the basic skeleton during pressing, whereby elemental fibers are probably due to their elasticity in micrometers and a small thickness filling the gap between the individual springs, which ultimately proves that the product is reinforced even in the prongs and protrusions, thereby avoiding their cracking, deterioration and peeling.

The invention is further illustrated by the following examples in which the composition is referred to as a weight concentration. Přikladl

The molding mass was prepared by containing 30% chopped glass fibers which consisted of a mixture of strands and a soluble and insoluble treatment of 50 mm. Glass strands with a soluble soluble diameter of elementary fibers 11, um and an insoluble strand composed of 200 elementary strands of average elemental fiber thickness15. Polyester composition based on 70% solution in styrene resin and an acid value of 22 mg KOH / g based on naltic anhydride, phthalic anhydride and propylene glycol in an amount of 25% homogenized with 1.5% magnesium oxide paste, 0.45% target. of butylperbenzoate, 1.2% zinc stearate, 32% calcium carbonate, 0.015% inhibitor, 3% styrene, 2.5% polyethylene, and the remaining pigment paste was applied to the polyethylene film between which the glass fiber was inserted. The prepreg thus prepared can be cured by pressing at a temperature of 130-160 ° C and pressing time of 1 to 10 minutes after thickening and film removal. The influence of the contents of the glass strands with the soluble modification of the mechanical properties of the thermoset is shown in the table. strand with soluble solution (° / w)

Bending-strength limit table (MPaWhen dry after boiling 0 10 50 80 148 133 155 142 176 153 192 169 Example 2

Similar to Example 1, a molding composition was prepared which contained squeezed fibers composed of 50% by weight of spun strands with a soluble treatment of an average elemental fiber thickness of 15 µm. The reinforced thermoset has a dry bending strength of 169 MPa and 141 MPa after boiling. The ratio of chopped glass fibers can most easily be prepared by simultaneously cutting the insoluble insoluble fibers, i.e. the coil from which the fibers are deposited into the mowers are fitted with both types of fiber.

Claims (3)

SUBJECT CLAIMS 1. Polyester thermosetting composite material reinforced with chopped glass fiber having a length of 3 to 60 mm, or even infinite, in an amount of 5 to 85% by weight, containing additives controlling mainly the stability, rheological and surface properties of the thermoset, The fiber composition comprises in its structure 10 to 85% by weight of elemental glass fibers and 90 to 15% by weight of chopped glass strands composed of 50 to 1200 elemental fibers. 2. Polyester thermosetting composite material according to claim 1, characterized in that the elemental glass fibers have an average thickness of 9 to 13 microns and the strand is spoiled from fibers having an average thickness of 15 to 25 microns. We claim: 3. A process for the production of a polyester thermosetting composite material according to items 1 and 2, characterized in that the composition based on a solution of unsaturated polyester resins, thickeners based on Group 2 metal compounds, polymerization initiators and additives controlling technological and utility properties the thermoset is applied to two separating films between which the chopped glass fiber is inserted, possibly even endless, such that the chopped glass fibers are composed of a mixture containing 10 to 85% by weight of glass strands with a coating soluble in an unsaturated polyester resin solution; after concentration, it cures, as a rule by pressing at elevated temperature. Severografta, n. p., plant 7, Most Price 2,40 Kčs