DE2027644A1 - - Google Patents

Description

The invention relates to improved curable molding compositions based on butadiene polymers. The expression "Molding compound" is used here in such a way that it is, in the broadest sense, compounds for compression molding, compression molding, Encapsulations, coatings, castings and the like.

Molding compositions of butadiene polymers are well known, particularly such compositions based on liquid polybutadiene odor liquid butadiene-styrene copolymers which contain a high proportion, such as 80 wt .- ^ ₁ in butadiene component. In this regard, reference is made to ournal, Märas I965, page 288, for example.

009851/2088

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Known molding compounds are valuable because of their high chemical resistance, thermal stability, chemical properties and electrical properties. However, they have the disadvantage of fairly short cure times at normal curing temperature, such as at 150 to 170 ⁰ C, using conventional proportions known peroxy curing agent. In general, lie in these known But ^ adienpolymeren about 65 ° fa of the butadiene content in the 1,2-form, ie in the form that produces a pendant to the polymer backbone vinyl group.

High vinyl budatienic polymers are known in the art such as, for example, in British Montecatini patents 835,752 and 85,615 which describe the syndiotactic, isotactic and amorphous (atactic) forms of 1,2-polybutadiene high in vinyl groups are. British Patent Specification 835 752 describes the curing of elastomeric 1,2-polybutadiene, are in the 80 to 90 i »double bonds Vinyl groups, using a kautschukhärtendera composition in the presence of antioxidant at 16O C for 30 minutes. A rubber-like product is obtained.

In contrast, the butadiene polymers in the present invention are homopolymerβ or mixed polymers with a strongly predominant butadiene1 where the monomer® butadiene «qIüo formation in the 1,3-Poeition in the 'monomer possesses *

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BATH ORIGINAL

The invention provides a practical curable 1,2-polybutadiene molding compound, resulting in somewhat flexible rigid products of high heat distortion temperatures and high hardness are curable. According to the invention, 1,2-polybutdiene polymer has mixed with a peroxy curing agent is, at least 80 $ of the butadiene content bound therein in the 1,2-form, i.e. in the form attached to the Polymer backbone provides pendant vinyl groups. The use of this polybutadiene with a high 1,2- |

Content of butadiene therein (hereinafter sometimes referred to as high vinyl butadiene polymer) a faster hardening rate, even if an antioxidant is contained in the mass, than one with Polybutadiene with about 60 to 70 $ 1,2-butadiene content

man

obtained which / so far for use with with peroxy curing agents proposed offset molding compounds.

The above-mentioned 1,2-butadiene content is determined by the ratio of the infrared absorption bands, see. ™ the above-mentioned British patent 854 615, page 1, Lines 68 to 74.

Butadiene polymer is used in the practice of the invention with a high vinyl content and high molecular weights (determined by the intrinsic viscosity) in the range from 1,000 to 1,000,000. This molecular weight range supplies molding compounds which, after being mixed with peroxy curing agents a melting temperature of around 130 ° C or

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own less. Using polymers with a molecular weight of up to about 50,000 results sufficient flowability at around 120 to 150 ° C, to fill a complicated shape in transfer molding. The molecular weight was found to have a Has an influence on the curing speed, with higher Values lead to higher speeds, such that a preferred minimum molecular weight of about 10,000 (determined by the intrinsic molar viscosity number).

In order to maintain these molecular weights without premature curing of the resin, it is desirable to incorporate it into the molding compound to incorporate an antioxidant-type polymerization inhibitor, such as a phenolic or amine antioxidant such as an antioxidant based of a 6-tert-butyl-m-fcresol derivative, such as 4,4'-butylidene-bis- (6-tert-butyl-m-cresol) or a hindered or blocked polyphenol or an antioxidant, such as • in secondary aromatic amine, for example N-phenylß-naphthylamine. An antioxidant is useful to a slurry of the polymer, as it is formed during the polymerization, added to the polymer particles to be coated and in this way to protect against the hardening effect of air * As mentioned above, dl Molding compositions according to the invention which contain a ceroxy curing agent contained, meltable at around 120 to 150 C, and with curing agents of suitable stability, they remain practically uncured at such temperatures, at least long enough for rental, such as

009851/2088. ₅

wise about 5 to 20 minutes, and if it contains a small amount, such as 0.1 to 10 wt .- ^ antioxidant. This Behavior allows not only the production of mixtures, but also the filling of a mold by injecting a " Melting or coating an object with a melt of the molding compound and subsequent hardening Heating the mass to a: · - Temperature of at least 120 C for a sufficient period of time to allow hardening cause. A high degree of cure can be obtained in a few minutes at 160 to 190 ° C., for example, with the specific temperature required depends on the choice of curing agent and its proportion.

The following examples illustrate the best mode contemplated for carrying out the invention. However, the concept of the invention is not limited to the specific details of the examples. A preferred one Polybutadiene for use in accordance with the present invention is normally granular crystalline, ayndiotactic 1,2-polybutadiene polymer. The usage of crystalline polybutadiene makes the production of the molding compounds by dry mixing processes both feasible vl · also attractive. Extra dome makes it easier to use of crystalline polybutadiene the granulation of the mixed Fornaaaae, if theeae in the form of an arc of a Walsenmühle kowt, vai the handling compared to the handling of known Gunni-like Polybutadieiunaasen, which on a mill was made easier.

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The polybutadiene used in the examples had unless otherwise noted, about $ 90 to $ 95 of the butadiene content bound in the 1,2-form and one intrinsic molar viscosity of about 0.4 dl / g, corresponding to a molecular weight of about 20,000 by the intrinsic molar viscosity (number average of about 10,000 by osmometry). The polybutadiene contained 0.3 wt. $ antioxidant. It wtr de after Process (a) produced as follows:

Method (a) j

A three-necked flask fitted with a magnetic stirrer is released from the air with dry nitrogen. 1.5 g (0.0042 mol) of cobalt IXX acetyl acetonate are placed in the flask and then added 2 ml of butadiene liquefied at 0 C. Become the catalyst 100 ml of benzene added. The mixture is stirred and kept at a temperature of 17 to 20 C, whereupon 1 »5 g (0.0130 mol) of aluminum triethyl are added. After stirring for 30 minutes, the contents are transferred to a filling device under a nitrogen atmosphere. which is set up for attachment to the reaction vessel and for its loading.

A “wide filling” is charged with 2095 g of butadiene and 2 ml (0.0122 mol) of diethyl funarate. Silk "soil • chickungeeinrichtungen be clean at · 1κam, dry autoclave of 3.8 1 reasonable with a glass lining

009851/2088, " ^? "

adds, which has been purged with nitrogen for 15 minutes. 525 β butadiene are added to the reaction vessel. Agitation is started and cooling water is circulated through the reaction vessel jacket until the temperature is 20-25 ° C. The pressure is about 2 atmospheres (30 psig). The catalyst solution is poured from the other filling device into the reaction vessel under the force of gravity. After 15 minutes, a further 525 g of butadiene are fed into the reaction vessel. The addition is continued at 15 minute intervals until all of the monomer has been added. The reaction is continued so that the total time is h hours.

The product is then discharged through the bottom of the RatkbLons vessel into a second kettle which is equipped with a vent line for unreacted monomer. This kettle contains 2 liters of isopropyl alcohol and 50 ml of hydrochloric acid. Then a nitrogen flushing device is connected to the reaction vessel so that nitrogen flows through the bottom discharge line below the liquid surface in the? lower boiler flows. The nitrogen flush is carried out for 15 "minutes. The product is filtered off from the deactivating medium and transferred to a mixer (Waring) which contains 1.5 l of isopropyl alcohol and 3.4 g of commercially available blocked polyphone oil" antioxidant ("Irganox" IO76). The resin is mixed for 15 minutes and filtered. It is transferred to floors and placed in a vacuum oven at 50 ° C. for 6 hours

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dried. 680 g of a white granular material are obtained Product. The resin has a reduced viscosity of 0.40 as measured at a one percent concentration in Decahydronaphthalene at 80 C, which corresponds to a molecular weight (M) of about 20,000, according to the formula »

Basic molar viscosity number = 1.53 x 10 M ⁰ ' ⁸ .

- See Schildknecht "Vinyl and Relates Polymers"

(John Wiley & Sons, Inc., N.Y. 1952), pp. 30-31.

The preferred curing agents are paroxy compounds with half-lives of at least 1 minute at I30 C. The molding compounds expediently contain a filler such as glass fibers, asbestos, finely divided silica, clay, Aluminum oxide, calcium carbonate, talc, powdered Graphite or the like, as well as a mold lubricant such as calcium te arate or zinc stearate.

example 1

100 parts of 1,2-polybutadiene made by the process (a), with the aid of a mixing head for exerting shear forces with 2.5 parts of peroxy curing agent, especially 2,5-dimethyl-2,5-bis- (tert-butylperoxy) -hexyne-

o 3, at an initial temperature of about 110 C, the rose to about 137 C over about 20 minutes, mixed. This mixture melted at about 128 C. The mixing was stopped continued for about another 20 minutes after the mixture became dry then chilled. The cooled mixture was friable

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009851/2088

Consistency that allowed easy conversion into gimalia form, which is suitable for loading into a conventional molding press.

The mixture was in a mold with a cover plate fed, the shape being designed to give a buckle about 3 mm thick. the Press was heated to 130 C for about 10 minutes at sufficient pressure to keep the mold closed, whereby the mass became flowable and filled the cavity of the mold with some overflow. Then the Temperature increased to about 175 C and one hour on kept this height. The mold was cooled and the resulting buckle removed. From the originally A buckle was made of gram-shaped material a very hard and vitreous material, which showed that there was a very high degree of hardening among those used Conditions has been reached.

Example 2

This example illustrates the manufacture of a molded polybutadiene buckle by method (A) having a cure level which will give a heat distortion temperature according to ASTM Test D-6k8 of at least 250 ° C.

According to method (A) - 1,2-polybutadiene (100 It was divided as in Example 1 with 1.75 parts of the example 1 peroxy curing agent used mixed uad

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20276

deformed by compression molding into a test piece of 25 13 χ 3 mm. The temperature used (190 ° C) was that at which the curing agent has a half-life of 1 minute. This degree of hardening led to a heat deformation temperature (ASTM test D-648) of at least 250 ° C and a weight increase (as a result of solvent absorption) of 37 ° after immersing the test piece in toluene for 7 days at room temperature and then drying the surface.

In contrast, a 1,2-polybutadiene resin showed with 65 $ of the butadiene content in the 1,2-form and with a similar molecular weight (20,000) 54 wt .- ^ increase at the same test.

Even higher degrees of hardness down to the zero point of a change in weight are obtained by immersion for 7 days in various reagents, including 10% and 50% sodium hydroxide, 50% sulfuric acid, concentrated nitric acid, glacial acetic acid, pyridine, methyl ethyl ketone and xylene. Such high levels of hardness are obtained, for example, by using four parts of peroxy compound and at 175 ° C. for 30 minutes. A Shore D hardness as high as 88 can be obtained.

Example 3

This Beiapi ©! explains the production of a.with filler provided mass. A molding compound was made by Var »

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mix the following ingredients with chloroform to a tex-like consistency, then air dry and grinding on a roller mill for about 5 minutes formed at about 14O ° C:

1.2 polybutadiene of process (a) - 100 parts by weight; P caroxide curing agents of Example 1-5 parts by weight; hydrophobic calcium carbonate powder for

electrical use, all parts with

less than 8 microns in diameter - 330 parts by weight;

Glass fibers (3 well) - 50 parts by weight;

Vinylsilane (bonding agent

for glass) - 5 part by weight ^ j

Diallyl isophthalate (curing accelerator) - 10 parts by weight.

The resulting composition, which could be easily granulated, became the crumbly press molding apparatus of Example 1 supplied. The mass was made by compression molding

Cured at 190 ° C for 10 minutes.

The hardened mass initially showed after heating in one Oven in air has the following properties when using Standard tests:

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009851/2088 ORIGINAL BATHROOM

Properties of a thermoset sample - room temperature

Tensile modulus (kg / cm '~)

maximum tensile strength (kg / cm ⁴ )

extreme elongation ($> ) flexural modulus (kg / cm) flexural strength
(kg / cnT)

Arc resistance (Säcunden)

wet arc tracking resistance (Minutes)

Heat distortion temperature (according to ASTM test D-648)

initially after 1 day after 20 days at 200 ° C

at 200 ^° C

0.18x10- '

239

462 188

27 240 ° CO, 17 x 10 ⁵ O, 16 x 10 ⁵

229 1.7

541

186

0.3

186

Properties of the heat-hardened specimen at 200 C

• j

Tensile modulus (kg / cm)

extreme tensile stress (kg / cm) extreme elongation (%)

Flexural modulus (kg / cm)

ο Flexural strength (kg / cm) 0.08x1.0 ^J 67

0.9

0.27x10 ⁵ 197

-U-

009851/2088

Example 4

400 parts of finely divided silica filler were in using a Sigma mixer at room temperature for 2 minutes

1.5 parts of a commercial vinylsilane binder for glass mixed. 2/5 (160 parts) of the mixture were removed, and 93 »4 parts, amorphous, atactic 1,2-polybutadiene, which is soluble in ether and containing about 85 % of the butadiene content in 1,2-form, were combined with the mixer

6.6 parts of diallyl xophthalate prepolymer ("Dapon M" from FMC Corporation) were added. This polybutadiene had a molecular weight of about kO, 000 to 45,000. The kneading action of the mixer produced a thick dough in about 3 minutes. For this purpose, 2.5 parts of di-C ^ -cumylper oxide and then the remaining 160 parts of filler-binder mixture were added. Mixing was continued for a total kneading time of 5 minutes.

The (remisch was then blended on an unheated roller mill for about 5 to 6 minutes, during which time a Dozen final passes were made (procedure whereby The mixture is removed from the rollers as a sheet, the sheet is rolled up and the ends are rolled up again inserted between the rollers of the mill), at the end this time the distance between the rollers was widened, so that the finished sheet mixture was about 6 mm thick. The resulting arch was in suitably large Cut pieces for molding.

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The mass became test sticks at about 150 ° C during 5 minutes and press molded at 680 at (10,000 psig), and the rods were post cured in an oven at 135 ° C for 2 hours. The molded pieces had a

Flexural strength of 773 kg / cm and a flexural modulus (both for Type I samples per ASTM test D-790) of

6.2
0.106 10 kg / cm. The heat distortion temperature (ASTM D-648) exceeded 220 ° C.

Example 5

The atactic 1,2-polybutadiene of Example k (100 parts) was mixed with the same peroxy curing agent in the same proportion (1.75 parts), as in Examples 1 and 2, and was as in Example 2 for 10 minutes 190 C molded under pressing. The resulting test piece was subjected to a 7-day immersion test in toluene as in Example 2. A weight gain of 37 ^{ ß> was recorded for this test, ie the same weight gain as for the test with the syndiotactic high vinyl 1,2-polybutadiene in Example 2 above,

Example 6

A roller mill xvurdo heated until the front roller 121 C! and the Hinterwalsse had 38 ⁰ C »Then 20 parts of polybutadiene, which had been prepared according to method (A), were gradually added with an ongon roll gap between the rolls until the resin formed an arch on the hot roll. Then a mixture of 80% was added over 5 minutes

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BATH

Parts of finely divided silica filler, 0.2 part of zinc stearate and 0.2 part of vinylsilane (glass binder) were added. Finally, three parts of di- ^ N-cumyl peroxide were gradually added over the entire nip. The grinding was continued for a further 5 minutes, then the mass was removed as a sheet, rolled up and, in a rolled up form, inserted again with the ends between the slightly spaced-apart pins. This procedure of introducing the rolled up material as between g di «rolls was repeated 15 to 20 times. Finally, the mass was removed from the mill as a sheet, cooled and ground into granules in an ordinary plant.

This mass was made by pressing under less severe conditions than in Example 3, i.e. at about 150 C during molded about 1 minute. The product had a heat distortion temperature (naciiAS ™ test D-648) of at least 250 ° C.

Example 7

Components:

20 parts of crystalline 1,2-polybutadiene, 80 parts calcium carbonate,

3 parts of di-öS-cumyl peroxide,

5 parts glass fiber filler (3 well), 0.5 part vinyl silane binder.

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The above ingredients were fed to a conventional ball mill and then mixed for 10 minutes. The resulting dry blended composition was sufficiently homogeneous for use in molding, especially in applications where shear forces are applied, such as injection molding or transfer molding.

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Claims (6)

Claims 1.) Curable 1,2-polybutadiene molding compound with a peroxy hardener, characterized in that the polybutadiene has at least 80% of the butadiene content the 1,2-form and its monomeric butadiene Has double bonds in the 1,3 ~ positions. 2.) Molding composition according to claim 1, characterized in that the 1,2-polybutadiene is normally granular, crystalline is syndiotactic 1,2-polybutadiene. 3.) Molding composition according to claim 1 and 2, characterized in that the polybutadiene has a molecular weight, determined by the base molar viscosity number, of at least 10,000, the peroxy curing agent has a half-life at L30 C of at least 1 minute and the mass about 0.1 to 10 wt -. ° ß> contains antioxidant. 4.) Molding composition according to claim 1 to 3, characterized in that it contains a filler. 5 · β process for the formation of a polybutadiene «, characterized in that a molding compound is produced in the molten state by mixing a polybutadiene from monomeric! 1,3-butadiene and a peroxy bond at a temperature "not above 1.50 C" forms, the polybutadiene having at least 80% of its butadiene content in the 0 0385 1/20 88 ~ ⁱ⁸ " BATH ORIGINAL 1,2-form contains bound, a molecular weight, determined according to the intrinsic molar viscosity, of at least 10,000 and about 0.1 bxs 10 (} ew, - / o Contains antioxidant and the peroxy compound has a half-life at 130 C of at least 1 minute. and thereafter the resulting mixture to a temperature ο
heated from at least -150 C long enough for the molding compound to harden up to a heat deformation temperature of at least 250 C » 6.) Method 'according to Aaspruich 5 »characterized in that the polybutadiene is syndiotactic 1,2-polybutadiene used" BATH ORIGINAL