DE1923598A1 - Process for the production of hard synthetic resin articles - Google Patents

Description

Description of the patent application

SHElI INTERNAiDIONALE RESEARCH IiAATSCHAPPIJ N.V. Carel van Bylandtlaan 30, The Hague / Netherlands

concerning

( Method of making hard synthetic resin articles.

The invention relates to a method of manufacture of hardening synthetic resin objects such as electrical insulators.

British Patent 1,095,743 describes a process for the manufacture of hard-to-burn hard Plastic objects by hot curing a mixture containing at least 5 wt .- # halogen, which in addition to a polyepoxide and a polycarboxylic anhydride contains a polyester obtained by reacting a polyol with a halogenated dicarboxylic acid anhydride such as hexachloroendomethylene tetrahydrophthalic anhydride (Chlorinated anhydride). However, such hardened articles are inadequate because of their inefficiencies Creep resistance cannot be used as electrical insulators.

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In British Patent 1,008,268 was also proposed to produce weather-resistant electrical insulators by using a cycloaliphatic polyepoxide with a cycloaliphatic or aliphatic polycarboxylic acid anhydride hardens as a hardener. It has now been found, surprisingly, that cast parts with improved dust and can establish fog resistance when maii the last. The mixtures described are used, which also contain a halogen-free, non-aromatic, hydroxyl-rich polyester contain'. One then also has the advantage that the production costs for the mixtures are reduced because Polyesters are generally much cheaper than polyepoxides.

The invention / is therefore a method for Manufacture of hard plastic objects, such as electrical insulators, which is characterized in that one Mixture of

(a) a halogen-free, non-aromatic polyepoxide,

(b) a halogen-free non-aromatic polyester with a Hydroxyl content of at least 30 meq OH / 100 g and one Acid number of less than 15 mg KOH / g, which is a reaction product of a halogen-free, non-aromatic Polyol with at least three hydroxyl groups per molecule, a halogen-free, non-aromatic polycarboxylic acid or its anhydride and a glycidyl ester of an aliphatic or cycloaliphatic monocarboxylic acid, in which the carboxyl group on a tertiary or quaternary Carbon atom sits j and

(c) a halogen-free non-aromatic polycarboxylic acid anhydride . , / ""

produces and the mixture cures by heating to a temperature of 80 to 200 ^{0 G.}

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Epoxides or mixtures of epoxides are referred _{to as polyepoxides 9} which have on average more than one epoxy group per molecule »The expression" polycarboxylic acid (or anhydride) "* also refers to dicarboxylic acids and their anhydrides.

As for the halogen-free non-aromatic polyepoxides, their epoxy groups may be terminal, i.

CHp - be CH groups or they can be in a middle position are located. The polyepoxides can be saturated or unsaturated, aliphatic or cycloaliphatic and can optionally be may be substituted with substituents such as hydroxyl and alkoxy groups. They can be monomeric or polymeric. The usage of liquid polyepoxides ^, i.e. those with a viscosity of less than 500 poises at 25 C, that facilitates Handling of the mixtures according to the invention,

The cycloaliphatic polyepoxides are preferred. Examples are diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, epoxidized vinylcyclohexane, the epoxidized dimer of cyclopentadiene, bis (2,3-epoxycyclopentyl) ether and the diglycidyl ether of hydrogenated 2,2-bis (4-hydroxyphenyl) propane. Very good results were obtained with 3,4-epoxycyclohexylmethyl-3 ', ^ - epoxycyclohexane and in particular with 3,4-epoxy-6-methylcyclohexyl methyl-3 ^l, 4'-epoxy-6'-methylcyclohexane.

Component (c) in the process according to the invention is the anhydride of a halogen-free, non-aromatic polycarboxylic acid with at least one anhydride group. The anhydride

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can be saturated, unsaturated, aliphatic or cycloaliphatic. Examples s ₄ ind: tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride and dodecylsuccinic anhydride.

The liquid under Normalurastanden or melting at a lower temperature (below 60 ⁰ C) anhydrides, in particular hexahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylendomethylenetetrahydrophthalic are preferred.

The component (b) is a halogen-free, non-aromatic one Polyester with a hydroxyl content of at least 30 meq. OH / 100 g and an acid number of less than 15 mg KOH / g. The polyester is made (by reacting a halogen-free, non-aromatic polyol with at least three hydroxyl groups per molecule with a halogen-free non-aromatic Polycarboxylic acid or its anhydride and a glycldyl ester an aliphatic or cycloaliphatic monocarboxylic acid in which the carboxyl group is on a tertiary or quaternary Carbon atom sits. Examples of suitable polyols are glycerol, pentaerythritol, 1,2,6-hexanetriol, trimethylolpropane, partially hydrolyzed polyvinyl acetate and polyvinyl alcohol. The polycarboxylic acid half is preferably through into the polyester Implemented reaction with hexahydrophthalic anhydride. as Glycidyl ester is preferably the commercially available product available under the protected trade name "Cardura" E, a glycidyl ester of a <* - branched, saturated monocarboxylic acid with 9-11 carbon atoms. Using this Glycidyl ester improves the water test resistance and flexibility of the cured products. For calculating the ratio from carboxyl to hydroxyl groups in manufacture

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of component (b), each glyeidyl group is two hydroxyl groups equivalent to. The glycidyl ester should not be used in a molar excess can be used over the polyol.

Generally speaking, the proportions of the constituents from which the polyester component (b) is produced are preferably selected so that a polyester is formed whose hydroxyl content is in the range from 100 to 500 meq OH / 100 g. The acid number of component (b) is less than 15 and is preferably below 10 mg KOH / g. If the anhydride of a polycarboxylic acid is selected for the preparation of component (b), each anhydride group is equivalent to two carboxyl groups. The polycarboxylic acid anhydrides are preferred for the production of the polyesters, but the corresponding acids themselves can also be used. The ratio between polyol including glycidyl ester and polycarboxylic acid or its anhydride is usually chosen so that 1.6 to 2.2, preferably 1.75 to 2, hydroxyl groups are present for each carboxyl group. The formation of the polyester may be effected by heating the ingredients for 1 to 10 hours or more to a temperature of 150-250 ⁰ C, until the acid number dropped to the appropriate value. If necessary, an esterification catalyst can be used.

The ratio in which the components (a), (b) and (c) are used according to the invention, can vary within wide limits; each anhydride equivalent of component (c) is preferably at least 0.5 epoxy equivalent of component (a) and 0.05 to 1 hydroxy equivalent of component (b). In terms of the amount of anhydride and polyepoxide As used herein, the term "equivalent" refers to that amount of anhydride, which one needs to have an anhydride group for

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each epoxy group in the polyepoxide involved in curing To make available. You get the best results when the anhydride is used in an approximately equivalent amount, preferably in an equivalence ratio of 1: 0.8 to 1: 1.2 for; u Epoxy used to anhydride groups.

Preferably, one uses a Härtebese 'leunigfr In small amount, for example from 0.01 to 10, in particular of Oil. M «2 weight fit calculated on the total weight of components (.), (B) and (c). Suitable accelerators are, for example, tertiary amines or their salts, such as triethylamine, 2,4,6-T-La- (dimethylaminomethyl) phenol, benzyldimethylamine, C ^ -äTethylbenzyldimethylamin, N-alkylimidazoles and alkali alcoholates, such as Sodium alcoholate, obtained by dissolving urodium metal in 2,4-dihydroxy-ß-hydroxymethylpentane.

You can also fillers, plasticizers, halogen-free additives to make the masses difficult to burn or to dye, use} glass fibers, asbestos, quartz powder or silicic acid may be mentioned as additives.

The hardening usually takes place at temperatures above 80, preferably at 100-200 ^° C.

The following examples A, B and H are embodiments of the process according to the invention. Examples C, D ₅ E, P, and G correspond to the prior art and serve to Mächweis the superiority of the process according to the invention by comparison. Example C corresponds to British patent specification 1,008,268, example D corresponds to British patent specification 1,095,743j Examples E, F and G use an aromatic polyepoxide to show the importance of the absence of aromatic groups.

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Examples

The castings used were prepared by curing the compositions A to H (described below) by 16-hour heating at 140 ⁰ C in the presence of a Härtebeschleuni-. ge rs.

The suitability of the hardened castings as electrical insulators was tested by determining the tracking resistance in accordance with BIN 53480 (VDE 0303, part 1 / 9.64, method KA, for which test solution A was used) and its resistance to dust and mist according to ASTM, D 2132-62 T (but for which 0.31 cm thick specimens were used).

The Polyster used are the following «

Polyester A (non-aromatic, chlorine-free; used in Examples A, B, E, Ϊ and H) s produced by heating hexahydrophthalic anhydride (trade name ¹¹ CARDURA ¹¹ E, protected for the glycidyl ester of a c * -branched saturated monocarboxylic acid with 9 to 11 carbon atoms) and glycerol in a molar ratio of 1.0 _f : 0.5: 0.6; the hydroxyl content of this polyester A was 256 mXq OH / 100 g and its acid number was 5-7 mg KOH / g.

Polyester B (non-aromatic, containing chlorine; used in Comparative Examples D and G): produced from hexachloroendomethylene tetrahydrophthalic anhydride and glycerol (oil ratio 1: 1.2); Hydroxyl content 325 meq OH / 100 g, acid number 7.2 mg KOH / g.

The following batches were made and cured;

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Α «a mixture of 100 g of 3,4-epoxycyclohexylmethyl-3 ·, 4'-epoxy-

cyclohexane carboxylate (with an epoxy equivalent weight of 135 and one Viscosity of 3.6 poises at 25 ° C)

105 g. Hexahydrophthalic anhydride and 100 g polyester A

was cured in the presence of 12 g of an accelerator (registered trade mark "DY 065", a Ciba product). The 16-hour heating of the mixture at HO ⁰ C was preceded by a gelling period of 2 hours at 80 ⁰ C. The service life of the mixture at 50 ^° C. was more than 5 h. The casting had a Barcol hardness of 39 and a Vicat softening temperature of 90 ^° C. with a penetration depth of 0.1 mm.

Test A was repeated, but the 3,4-epoxycyclohexylmethyl-3 ¹ , 4'-epoxycyclohexane carboxylate was replaced by an equal amount of 3,4-epoxy-6-methyl-cyclohexylmethyl-3 ', 4'-epoxy-6 methylcyclohexane carboxylate with an epoxy equivalent weight of 150 and a viscosity of .18 poises at 25 ° C. The service life of the mixture at 50 ° was also more than 5 hours. The Barcol hardness and the Vicat softening temperature (at 0.1 mm penetration depth) of the casting obtained were 40 and 88 ^° C., respectively.

C: (for comparison)

The comparison samples were prepared as under A, with

however, polyester A was omitted. _;

D: (for comparison)

The comparison pieces were produced as under A above, but with the. Polyester A through the chlorine-containing polyester B was replaced.

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E: (for comparison) A mixture was made from

10Og of a liquid glycidyl ether of

Diphenylolpropane with an epoxy equivalent weight of 200 and a viscosity of 100 poises at 25 ⁰ C,

74 g phthalic anhydride and 100 g polyester A.

The mixture was in the presence of 0.6 g of x-methylbenzylamethylamine cured as a hardening accelerator, but no gel period was used.

Q: (for comparison)

The procedure was as in E, except that the phthalic anhydride was replaced by 77 g of hexahydrophthalic anhydride.

G: (for comparison)

It was worked according to P, but the polyester A was replaced by the chlorine-containing polyester B.

H: a mixture of 15 g diglycidyl ester of Hexahydropb.ial-

acid

15 g of polyester A and 13 »1 g of hexahydrophthalic anhydride

was cured according to the method used under A above in the presence of 0.09 g «^ -Methylbenzyldimethylamin. The service life at 50 ^° C. was more than 5 hours. The casting had a Barcol hardness of 27 and a Vicat softening temperature of 7O ^ ⁰ C at 0.1 mm penetration depth. -

The test results are shown in Table I.

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Table I.

Composition of the castings

Tracking resistance
(VDEO 303, part 1 / 9.64)

Dust-mist resistance (ASTM, D 2132-62 T)

Type

Aromatics content

Chlorine content wt .- # Cl

Valuation *

Depth of erosion

Carbonization

Hours to failure

Type of failure

CD A. O CD B. OO 00 - C. • D K) E. OO F. G

O O

D O

KA 3c
KA 3c

0.9
0.9

easy
easy

625 1000

Erosion.

O O

47 .25

16

15th

16

KA 3c 0 , 9 easy KA 3b 1 ,8th strong KA 3a 7 * 2 very strong KA 3c 0 , 9 middle KA 1** • mm

475

Charring (creeping track)

♦ In this attempt to determine the creepage resistance, the relevant Test solution in measured drops' with a certain speed between dropped the poles of two electrodes, which are under a voltage of 380 V. and are arranged close together on the material to be examined. The review The tracking resistance is based on the number of drops that are necessary are to create either a short circuit or a certain depth of erosion. The evaluation key is shown in Table II.

** short circuit after 3 drops,

*** The highest rating for the tracking resistance is KA 3c; when the rating is lower, the dust / mist resistance is not determined.

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Table II

Evaluation number of drops Short circuit

Depth of erosion

KA 1 KA 2 KA 3a KA 3b

KA 3c

1-10 11-100 101 101

101 yes

No no

no

deeper than 2mm

between 1 and 2 mm

less than 1 mm

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Claims

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Claims (10)

Pat ent claims 1. Method of manufacturing, of hard synthetic resin objects, such as electrical insulators, characterized in that (a) a halogen-free non-aromatic Polyepoxide, (b) a halogen-free, non-aromatic polyester with a hydroxyl content of at least 30 meq. OH / 100 g and an acid number of less than 15 mg KOH / g, the the product of a reaction between a halogen-free non-aromatic polyol with at least three hydroxyl groups each: Molecule, a halogen-free non-aromatic polycarboxylic acid or its anhydride and a glycidyl ester of an aliphatic or cycloaliphatic ffionocarboxylic acid, in which the carboxyl group is on a tertiary or quaternary carbon atom; and (c) the anhydride of a halogen-free non-aromatic polycarboxylic acid mixed and that Mixture hardens by heating to 80 to 200 ° C. 2. The method according to claim 1, characterized in that g e k e η η -. draws that a cycloaliphatic ^ polyepoxide is used as the polyepoxide. 3. The method according to claim 1 or 2, characterized in that a polyepoxide with a _; Viscosity less than 500 poises at 25 ° C used. 4. The method according to any one of claims 1 to 3, characterized characterized in that the polyepoxide used is 3,4-epoxycyclohexylmethyl-3 ', .4'-epoxycyclohexanecarboxylate, in particular 3,4-epoxy-6-methylcyclohexylmethyl-3', 4'-epoxy-6'-methylcyclohexanearboxylate, used. 9 0 9 8 4 8 /.1.2 at -JT- U-36 193 Al 5. The method according to any one of claims 1 to 3 »thereby characterized in that the polyepoxide used is diglyeidyl hexahydrophthalate used. 6. The method according to any one of claims 1 to 5, characterized in that the polycarboxylic acid anhydride hexahydrophthalic anhydride is used to produce component (b). 7. The method according to any one of claims 1 to 6, characterized in that there is one as component (b) Polyester with a hydroxyl content of 100 to 500, meq OH / 100 g used. 8. The method according to any one of claims 1 to 7, characterized characterized in that as component (c) a Polycarboxylic anhydride with a melting point below 60 ° C., in particular hexahydrophthalic anhydride, is used. 9. The method according to any one of claims 1 to 8, characterized characterized in that a mixture is used, in which the equivalence ratio of components (a), (b) and (c) per anhydride equivalent of component (c) is at least 0.5 epoxy equivalent of component (a) and 0.05 to 1 hydroxy equivalent of component (b). 10. The method according to any one of claims 1 to 9> characterized in that a hardening accelerator in a proportion of 0.1 Ms 2 fo of the total weight of components (a), (b) and (c) is added to the mixture before hardening. , 90-9-848 / 128 ί