CS233224B1 - Method of pre-impregnated polyester glass mat making - Google Patents

Abstract

The invention relates to a process for the production of polyester glass mat to which they are added glass sheets in combination chopped and infinitely oriented, thereby reducing overall glass contents, at the same time increasing mechanical properties and a better surface. Polyester glass mat is prepared in such a way that the prepared composition is between the polyethylene foils, between which simultaneously adds a combination of glass fibers. The mat made in this way after maturing process by pressing technology under heat and pressure

Description

(54) Method of making pre-impregnated polyester glass mat

The invention relates to a method of manufacturing a polyester glass mat to which glass fibers are added in the form of a combination of chopped and infinitely oriented torsionless, thereby reducing the overall glass content while increasing the mechanical properties and improving the surface. Polyester glass mat is prepared team ^- sp6sobom that are ready Ijompozícia deposition between polyethylene films, among which simultaneously adds a combination of glass fibers. After maturing, the mat thus prepared is processed by means of heat and pressure pressing technology.

The invention relates to a process for the production of polyester pre-impregnated glass mats, also referred to as prepregs, from which high mechanical strength products are produced by the application of heat and pressure.

The preparation and processing of prepregs is well known and the literature describes its detailed methods.

Industrial prepregs are produced by impregnating chopped strands, mats or fabrics with a polyester composition consisting of unsaturated polyester resins, fillers, initiators, inhibitors, release agents, pigments, surfactants, flame retardants, and the like. In order to make the prepregs well processable and non-tacky, metal compounds which are preferably used in the form of pastes in special surfactants, as described in the description of the invention, are added to the composition.

AO 210,365, 211,005.

The prepregs are stored for a longer period of time and are processed by hot and pressure pressing technology. When using prepregs for the manufacture of the articles, a prepreg is prepared from one or more layers, which is placed in the center of the mold and pressed to obtain a compact by heat and pressure. Typically, a shear is used whose surface corresponds to approximately 60% of the surface of the molded article, which means that the glass fiber composition must be spun in all directions in order to completely cover the mold and to make the molding homogeneously reinforced.

The article produced by this method is usually handed over without being treated after compression and must therefore have certain properties. In particular, it must have good mechanical properties and the desired surface appearance. Essentially, two criteria determine good surface appearance. PodTa franc. pat.

398 702, the glass fiber must not protrude from the molding surface. Haatom must not be detectable that the material is reinforced with glass fibers. In addition, the fibers must not be visible due to the color difference with the basic bituminous material. These properties are assured by the substantially specific properties of the glass fibers provided by the surface treatment.

The appearance of the moldings and, in particular, the gloss of the moldings is improved by the addition of copolymers as described in the description of the invention. AO 198 115, 210 365. The principal property of mechanical properties is glass fiber, its type, content, length, and orientation. It is known that increasing the mechanical properties of prepreg and moldings thereof is assured by the use of special resins, but mainly by increasing the content of glass reinforcement in the prepreg in the form of chopped

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roving up to 40%,

The disadvantage of this method of increasing the mechanical strength is that with increasing glass content, the surface quality decreases, production costs increase and there is considerable dispersion in the mechanical properties of the compacts.

The above drawbacks and problems are eliminated using the technology of the present invention by adding glass fiber in the form of a combination of chopped and infinitely oriented twistless fibers in a ratio of 1: 1 to 5) 0.5: 0.5, which is provided for twisting free of polyester pre-impregnated mats. by tangential unwinding from the outer surface of the rotating roving coil.

By using a combination of chopped glass fiber and endless grain oriented fiber, the overall glass content is reduced, while mechanical properties are improved and the surface is improved. The process according to the invention not only removes the above-mentioned drawbacks, but at the same time reduces the production costs.

The invention is 3al. As exemplified.

EXAMPLE

A polyester pre-impregnated glass mat was prepared by first passing under the disolver as the speed was gradually increased up to 1100 rpm. mixed co-oposition composed:

- unsaturated polyester resin

- styrene

- Initiator

- pigment paste

- inhibitor

- separator

- ground limestone

- gloss-enhancing additives

- thickener

23.65 wt. d. 2,365 wt. d. 0.44 wt. d. 4.377 wt. d. θ ', 012 wt. d. 1.314 wt. d.

35.477 wt. d. 2,365 wt. d. 0.35 wt. d.

Upon complete homogenization of the above components, the prepared composition was applied between polyethylene films between which a glass fiber in the form of a combination of chopped roving 50 mm in length and 22: 8 twisted continuous filaments was added simultaneously. parts.

The polyester mat thus prepared, after being wound into approximately 50 kg of wrapping, was aged for 10 days and subsequently pressed under heat and pressure. The mechanical properties of the molding in the direction of fiber orientation of the polyester mat are: bending strength 320 MPa, impact strength 18 J / m. For comparison, moldings evaluated from a polyester mat prepared in an analogous manner except that a fiber in the form of a chopped roving of 50 mm, i.e. a chopped roving, of the same glass fiber content, was used. j. without filament, they reached mechanical strengths: a flexural strength of 155 MPa, an impact strength of 8 J / cm.

Example 2

Polyester pre-impregnated glass mat prepared in a manner analogous to Example 1 except that a combination of chopped and continuous filaments in a ratio of 20:10 parts by weight was used. Mechanical strengths of the compact: flexural strength 330 MPa, impact strength 16 J / cm.

Example 3

Polyester pre-impregnated glass mats according to Examples 1 and 2 were used to manufacture bumpers for automobiles.

The moldings obtained exhibited higher and more uniform mechanical strengths and substantially higher quality surfaces than moldings with 38% glass content. The impact toughness values of the bumper made of prepreg with 38% chopped fiber 2 were 7 J / s, compared to those of the bumper made according to Examples 1 and 2, which were 13 J / cm.

The use of the invention is advantageous in those areas of industrial products where high mechanical strength is required in one direction. By utilizing the invention, it is possible to provide replacement of metal, plastic materials, with a view to achieving high mechanical strengths and low specific gravity.

Claims (2)

OBJECT OF THE INVENTION A method for producing a pre-impregnated polyester glass mat, characterized in that glass composition retarders and other conventional glass additives are added to the composition of unsaturated polyester resin, styrene, initiators, pigments, inhibitors, ground fillers, separators, stabilizer thickeners and other conventional additives. fibers in the form of a combination of chopped and infinitely oriented in a ratio of 1: 1 to 5.5: 0.5 parts by weight. 2. A method for producing a pre-impregnated polyester glass mat according to claim 1, characterized in that a continuous twisted glass fiber is added. Severography, n. p., MOST