DE2148691A1 - TRAENK MATERIAL FOR GLASS FIBER MATS - Google Patents

Description

SIEME] JS AKTIEHGESEILSCHAPT Erlangen, September 27, 1971 Berlin and Munich Werner-von-Siemens-Str. 50

VPA 71/7580 Td / Dm

Impregnating compound for glass fiber mats

The production of large, in particular large-area molded bodies from powdery or short-fiber molding compounds is difficult. The pressing technique with resin mats has proven itself here. She is also having particular success in the field of electrical engineering used, especially when it comes to producing large-area parts.

For soaking carrier materials such as natural or synthetic fibers such as glass fibers, glass silk fabrics, glass fiber mats, epoxy resins can also be used. Hiring a Appropriate viscosity plays a significant role in the impregnation of carrier substances. To the extremely thin threads well wet, the impregnating resin or the impregnating mass must have a low viscosity and the impregnated material must be used have good flowability when exposed to heat and pressure, in particular to enable complicated shaping. On the other hand, a high viscosity is required for the pressing and flow properties, so that the impregnating resin during the pressing process does not flow out of the carrier material. These materials are also supposed to be from a manufacturing and economic point of view Harden grounds as quickly as possible.

It has now been found that impregnating compositions for glass fiber mats, fabrics or other fibrous mat products which contain a post-purified epoxy resin based on "bisphenol A" with a chlorine content of at most 0.1% by weight no longer show the disadvantages described. Very particular advantages are up to 0.05 percent at the smallest possible chlorine content, in particular traces -. $> Reached. Above all, the curing times are much shorter than those required for the usual production of laminates. The drinking

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masses according to the invention are pourable and cause a good impregnation of the carrier materials. The cured moldings produced therefrom have good mechanical and electrical properties Properties on. It occurs even in the presence of Moisture does not cause electrolytic corrosion, which is of crucial importance for electrical engineering components,

on

A low-pressure molding compound for encasing electrical components, in particular semiconductor components by the transfer molding process, consisting of a post-cleaned bisphenol Α-based epoxy resin with a chlorine content of at most 0.1 wt .- ^ has already been proposed. With such molding compounds, however, large-area W and thick-walled molded parts, such as those required for many applications in electrical engineering, cannot be produced.

The impregnation of the carrier substances with the impregnating composition according to the invention can be carried out with the usual equipment by brushing on, spraying on or, best of all, with the help of a roller frame will. In particular, commercially available glass fiber mats, which are only weakly bound, can be used here will. After soaking, the soaked glass fiber mat, which is located between protective films, is laid out flat.

It has been found that the ambient temperature when the freshly soaked mats are displayed has a considerable influence on the shelf life. Storage temperatures below 20 ^° C. have proven to be particularly favorable.

The pre-impregnated with a post-cleaned epoxy resin with a chlorine content of at most 0.1 wt .- ^ according to the invention Fiberglass mats can then be cured into final shapes as usual with the application of pressure and heat.

The epoxy resins to be used can be obtained by reacting a polyhydric phenol such as 4,4'-dioxydiphenyldimethylmethane with, for example, epichlorohydrin. This production is described in detail in German patents 875 725 and 906 998, for example. The resins thus obtained, • preferably those with a melting point of about 42 ⁰ C,

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be. cleaned in known manner to a chlorine content of <0.1 wt -io.

Before curing, the impregnating compositions according to the invention can be combined with numerous fillers, pigments, lubricants and other additives which can make up to $ 150 of the solid epoxy resin. The prerequisite is that the fillers do not react with the reactive constituents of the mass and that they are practically chlorine-free. Common fillers include rock powder, glass powder, mica powder, chalk and quartz powder. Surface-treated fillers have proven to be particularly suitable.

One or more amines are preferably used as hardeners, for example isophoronediamine, cycloaliphatic amines and 4,4'-diaminodiphenylmethane.

Depending on the type of curing agent used, curing at 100 may be performed to 18O ⁰ O. Preferably temperatures are applied to 15O ⁰ G. The curing time depends on the conditions used and the hardener used. On average, the hardening is less than 90 seconds per mm of wall thickness.

With impregnating compounds, the epoxy resins purified according to the invention with a chlorine content of at most 0.1 wt .- $, significant advantages are achieved. So show with the invention Impregnating masses produced glass fiber press mats under the action of heat and pressure a good flowability, whereby in particular, complicated shapes are facilitated or made possible. The curing times are much shorter what has a higher throughput and thus a more efficient production. The mechanical and electrical properties the products obtained after curing are particularly favorable. A particular advantage is also in it see that in the presence of moisture no electrolytic corrosion occurs, which is especially true for electrical switches

matters.

Using the impregnating composition according to the invention can mechanically and electrically high-quality molded parts and laminates getting produced. Switch bushings produced from such glass fiber press mats are particularly notable due to high mechanical strength and good electrical properties the end.

The following examples are given to illustrate the invention.

example 1

720 parts by weight of a post-cleaned epoxy resin with an epoxy number of 0.55-0.58 and a chlorine content of less than 0.1 wt .- # are initially at 45 to a maximum of 60 ° 0 with 100 parts by weight. of a color pigment and 8.0 parts by weight. Zinfcetearate as mixed with the help of a stirrer. Thereafter, 205.0 parts by weight are added in portions. 4.4 ^t -diaminodiphenylmethane (DDM) added as hardener component. Finally, 805 parts by weight of a surface-treated chalk are added. After stirring for 1/2 hour, the mixture is homogeneous.

The pourable mixture is now used to impregnate commercially available glass fiber mats that are only weakly bound. the Impregnation can be carried out using known methods by brushing on, spraying on, but best done with the help of a roller mill will. After the soaking process, the soaked glass fiber mat located between protective films is laid out flat. It solidifies to a hard product within 24-36 hours at room temperature.

Corresponding cuts can be made after removing the protective film be pressed into electrically and mechanically high-quality molded parts. At a curing temperature of 150-160 ° C and one A hardening time of 90 sec / mm wall thickness is measured on standard test specimens achieves the following properties:

3098UV1155

245 H / mm ² 155 If / mm ² 125 mmN / mm 110 mmlft / mm 145 ⁰ σ 20th kV / mm 10 - * n »em 7th , 6 · 1Ο " ³ 4th , 72 KA 3c Level A,

Victory strength:

Tensile strenght:

Impact strength:

Notched impact strength:

Heat resistance according to Martens:

Dielectric strength:

spe ζ . Volume resistance:

Loss factor:

Dielectric constant:

Tracking resistance:

Electrolytic corrosion:

Example 2

720 wt. I. of a post-cleaned epoxy resin with an epoxy number of 0.55-0.58 and a chlorine content below 0.1 wt. - $> are initially at 40-50 ° 0 with 100.0 parts by weight. of a color pigment and 0.8 parts by weight. Zinc stearate mixed as a lubricant with the help of a stirrer. Then 173 parts by weight are slowly added. 3-aminomethyl-3 »5» 5-trimethyleyclohe: xylainin, added as hardener component. Finally, the addition is made of 805 wt. T. a surface-treated chalk. After stirring for 1/2 hour the mixture is homogeneous.

The further processing of this pourable mixture takes place as described in Example 1.

At a curing temperature of 150-160 ° 0 and a curing time of 90 sec / mm wall thickness, the following are used on Uorm specimens Properties determined:

Flexural strength: - : 8 U / 11SS 250 N / mm ² Tensile strenght: 140 If / mm ² Impact strength: 100 mmN / mm Notched impact strength: Martens: 85 mmir / mm Heat resistance according to 155 ° C. Dielectric strength: 21 kV / mm Specific volume resistance 3 «10 ^ n.cm

Loss factor: 7.1 <Γ ³

Dielectric constant: 4.68

Tracking resistance: KA 3c

Electrolytic corrosion: level A, 1

4 claims
0 figures

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Claims (4)

Claims 1. Impregnating compound for glass fiber mats or fabrics for production of press mats based on a filled, post-cleaned epoxy resin, characterized in that it contains an epoxy resin with a chlorine content of 0.1% or less by weight. 2. impregnating mass according to claim 1, characterized in that the chlorine content is below 0.05 wt .- ^. 3. Impregnating compound according to claim 1 and 2, characterized in that an epoxy resin with a melting point of about 42 ⁰ C is used. 4. impregnating mass according to claim 1 to 3, characterized in that that it contains the filler in a surface-treated form. 3098U / 1 155