CA1134859A

CA1134859A - Olefin-maleic anhydride copolymers

Info

Publication number: CA1134859A
Application number: CA000314474A
Authority: CA
Inventors: Heinz Beck; Karl H. Frassek; Werner Holtvoigt; Ambar N. Mukerjee
Original assignee: Akzona Inc
Current assignee: Akzona Inc
Priority date: 1977-10-28
Filing date: 1978-10-27
Publication date: 1982-11-02
Also published as: FR2407224A1; NL7810254A; ATA741678A; AU4103078A; IT1106083B; AU522877B2; SE7811177L; DE2748367A1; IT7851654A0; ZA785833B; JPS5471186A; AT364864B; BE871549A; BR7807119A; GB2006793A; GB2006793B

Abstract

ABSTRACT OF THE DISCLOSURE
Olefin-maleic anhydride copolymers having an average molecular weight from about 1000 to about 30,000 are disclosed.
The olefin is selected from the group consisting of branched and straight chain olefins containing from about 8 to about 24 carbon atoms, and mixtures thereof.

Description

~1 34859 BACKGROUND OF THE INVENTI~N

This invention relates to olefin-maleic anhydride copol~ners and their use as lubricants.
Olefin-maleic anhydride copolymers are well known.
The addition of at least 0.1% by weight of such a copolymer comprised of unsaturated maleic anhydride with styrene, an olefin, or an alkyl vinyl ether with alkyl groups having from 1 to 25 carbon atoms, to PVC, is taught by Belgian Patent 746,014.
The addition of such a modifying agent results in a considerable increase in the impact strength. For such a purpose, the co-polymers are added in a quantity from 0.1 to 5%. During rolling at temperatures between 149 and 204C, they are stable for up to 15 minutes, without the addition of a special lubricant to the PVC powder. It should be noted that for processing a rolling stability of lS minutes is inadequate.
The mixing of polyethylene terephthalate with ionic copolymers from ~-olefins and ~,~-unsaturated carboxylic acids, which likewise improved the impact strength, is taught by U.S.
Patent No, 3,435,093.
German Patent No. 2,015,162 teaches thermoplastic molding batches for injection molding purposes consisting of polyesters with a coating of 0.01 to 5%, by weight, based on the quantity of polyester, of an ionic copolymer of ~-olefins and salts of ~ unsaturated monocarboxylic acids or dicarboxylic acids containing ions of mono- to trivalent metals, resulting in plastic material, which after it had been shaped, was easy to remove from the mold. Thus, the copolymer derivatives are used as mold release agents.
The known olefin-maleic anhydride copolymer derivatives heretofore added to plastic masses before molding are unsuitable

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as lubricants, because the attained rolling stability is inadequate for requirements in plastic processing, even though the derivatives were added in considerably large quantities ~up to 5% by weight), as compared to typical quantities of lubricant additive.
In the known processing methods, plastics are shaped at a high temperature and under compressive loads. Under such conditions, the heated plastic mass tends to adhere to parts of the machine and the adhering material has a greater retention time in the machine, resulting in thermal degredation of the plastic, which in turn requires termination of the process. As a result of the thermal degredation, the processing of PVC is also accompanied by the splitting off of hydrochloric acid, which is due to the limited time in which the heretofore utilized stabilizers are effective.
In order to avoid the foregoing difficulties, lubri-cants and/or processing auxiliaries are added to the plastic powder in addition to the customary stabilizers before process-ing, which facilitate gelling, exert a favorable influence on the flowing of the melted mass, and inhibit adhering of the plastic to the heated metal surfaces. In the case of the lubri-cants, one may differentiate between internal and external lubricants. Good internal lubricants are, for example, fatty alcohols, as well as fatty acid partial esters of glycerin, such as glycerin mono-oleate and glycerin monostearate. Among the useful external lubricants with good release effects are fatty acid amides, fatty acid esters, natural, as well as synthetic, parafin hydrocarbon, low-molecular polyethylenes and hardened glycerides.

Selection, dosage, and combination of several types of lubricants depend upon the processing conditions, such as temperature, pressure, and characteristics of the components of the rnixture. In the past, plastics processor, in order to adjust to different processing methods, has been forced to employ combinations of different lubricants. The requirement for special mixtures for special cases had resulted in con-siderable expenditure for the processor. In addition, incompatibility effects, even if lubricant combinations are used, cannot always be avoided, since the required minimum lubricant additive quantities to attain freedom from adhesion have to be maintained.
Typically, lubricants are utilized in proportions from about 0.5 to about 5% by weight, based upon the weight of the plastic.
An object of the present invention is to create new olefin-maleic anhydride copolymers which are excellent lubri-cants for use in the shaping process of plastics, which have to be added to the plastic only in small quantities, and which can be adjusted in such a way in their effect as internal and ex-ternal lubricants, that there will be no risk of incompatibility and optimal processing conditions will become possible.

SUMMARY OF T~E INVENTIO~
There has now been discovered useful lubricants which may be utilized in the processing of plastics, the lubricants comprising olefin-maleic anhydride copolymers having an average molecular weight from about 1000 to about 30,000, wherein the olefin is selected from the group consisting of branched and ~. ~

:1~3~8S9 straight chain olefins containing from about 8 to about 24 carbon atoms, and mixtures thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As indicated, the olefin-maleic anhydride copolymers are made from olefins which contain from about 8 to about 24 carbon atoms. Good results are obtained with the olefin-maleic anhydride copolymers when the average molecular weight of the copolymer is from about 1,000 to about 30,000. Especially good heat stability may be achieved from lubricants wherein the copolymers are made up of maleic anhydride and olefins with from about 10 to about 22 carbon atoms. The copolymer may be com-prised of a wide range of olefin to maleic anhydride-constituents but typically the molar ratio of maleic anhydride to ole~i~ i5 from about o.a: 1 to about 1.8:1.

Because of the very simple synthesis method which may be employed, the olefin-maleic anhydride copolymers pursuant to the present invention are easy to prepare and thus are easily accessible.
The olefin-maleic anhydride copolymers are especially well suited as lubricants for the shaping processing of plastics.
Only small quantities of the lubricants need to be added to the plastic to be processed, at which levels they are fully effective.
All plastics processed by thermoplastic means, in particular, polyvinyl chloride, may be taken into consideration.
In order to insure easy processing and uniform dosages, the olefin-maleic anhydride copolymers pursuant to the present invention result in excellent lubricants in a preferred embodi-ment of the present invention, if they are present in a mixture with an aliphatic hydrocarbon with more than 12 carbon atoms ~` _ 5 -.:

1~34859 and/or aromatic hydrocarbons and/or esters of fatty acids with more than 7 carbon atoms and/or wax esters and/or fatty alcohols with more than 7 carbon atoms and/or wax alcohols. Preferably, the lubricants contain 10 to 90%, by weight, of the olefin-maleic anhydride copolymer.
In the polymer, the lubricants pursuant to the present invention do not result in any discoloration and also do not lower the stability, which is, however,observed with some prior art lubricants.
The high level of effectiveness and the lower quan-tities of necessary lubricants resulting therefrom improve the mechanical characteristics of the molded items. For example, the tensile strength and the Vicat value do not decline as much when plastics with the lubricants pursuant to the present invention are processed.
The good compatibility with liquid stabilizers should also be noted. The foregoing fact permits using the olefin-maleic anhydride copolymer lubricants for the preparation of ready-made mixtures to be used as additives in the processing of plastics, when mixtures contain stabilizer, lubricant, and other auxiliaries which are ready for use. Stabilizers suitable for such mixtures with the lubricant pursuant to the present invention are neutral and/or basic metal soaps and/or basic lead salts and/or calcium, barium, lead or zinc carboxylates and/or tin thioglycolate stabilizers, such as octyl or butyl tin thioglycolates.
The present invention is described in further detail in the following non-limiting examples.

.

EXAMPLE I
2.5 moles (740 g) of a C20 olefin (made by Gulf) and 2.5 mc,les t245 g) maleic anhydride are mixed with 200 g of xylene as solvent, on which occasion the reaction mixture in the reaction vessel is flushed with nitrogen and is brought to a reaction tem~erature from 120 to 170 C. In about 13 portions of 1.7 ml each, tertiary-butyl peroxide is added at intervals of 30 minutes. About 30 minutes after the last addition, the reaction mixture is cooled to room temperature. It is also possible to perform the copolymerization in such a way, that the maleic anhydride is added in portions, together with appropriate portions of tertiary-butyl peroxide. Referred to the maleic anhydride used, the conversion was in each case 95%.
The molecular weight of the copolymers was determined by means of gel permeation chromatography. This involves a method of high-pressure chromatography, in which a mixture is broken down in keeping with the molecular weight. A relation-ship exists between retention time and molecular weight, so that the molecular weight can be determined by using calibrating substances. Tetrahydrofuran was used as mobile phase, while a differential refractometer served as detector. The column was a microstyragel column of the firm T~aters Associates, as described in their company publication AN 143, of June 1974.
EXAMPLE II
` 100 parts of suspension polyvinyl chloride (K value 70) and 1 part of octyl tin sulfide stabilizer were premixed for one minute in a high-speed laboratory mixer with 0.15 parts of the lubricant pursuant to the invention (for details, see Table I). The mixture is plasticized for about 10 minutes on a 2-roller laboratory rolling mill with a roller diameter of 110 x 225 mm, a gap width of 0.8 to 1 mm, at a speed of about 20 rpm, and a temperature of 180C, whereupon the duration of rolling at 180C to reach a breakdown in sliding ~ - 7 -- : -1134~9 capability (adhering to a roller) and/or a breakdown in stabi]ity (brown discoloration of the film when the degradation point is reached) is determined.
The results of these rolling experiments, for lubricants pursuant to the invention, are compiled in Table I.
A PVC lubricant mixture, containing a customary lubricant mixture of 0.5 parts tridecyl stearate instead of the 0.15 parts of lubricant pursuant to the invention, adhered to the roller after only 39 minutes under the same conditions.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. An olefin-maleic anhydride copolymer having an average molecular weight from about 1,000 to about 30,000 wherein the olefin is selected from the group consisting of branched and straight chain olefins containing from about 19 to about 24 carbon atoms, and mixtures thereof.

2. The olefin-maleic anhydride copolymer of Claim 1, wherein the olefin is selected from the group consisting of branched and straight chain olefins containing from about 19 to about 22 carbon atoms.

3. The olefin-maleic anhydride copolymer of Claim 1, wherein the molar ratio of maleic anhydride to olefin is about 0.8:1 to about 1.8:1.

4. A lubricating agent comprising from about 10 to about 90% of an olefin-maleic anhydride copolymer having an average molecular weight from about 1,000 to about 30,000, wherein the olefin is selected from the group consisting of branched and straight chain olefins containing from about 19 to about 24 carbon atoms, and mixtures thereof, and the balance 1 or more members selected from the group consisting of aliphatic hydrocarbons with more than 12 carbon atoms, aromatic hydro-carbons, esters of fatty acids with more than 7 carbon atoms, wax esters, fatty alcohols with more than 7 carbon atoms, wax alcohols in mixture with neutral and/or basic lead salts, calcium, barium, lead carboxylates, zinc carboxylates, and tin thioglycolate stabilizers.

5. In a process for shaping processing of plastics, the improvement comprising adding to the plastic to be processed an effective amount of an olefin-maleic anhydride copolymer having an average molecular weight from about 1,000 to about 30,000 wherein the olefin is selected from the group consisting of branched and straight chain olefins containing from about 8 to about 24 carbon atoms, and mixtures thereof.

6. In the process of claim 5, the improvement wherein the olefin is selected from the group consisting of branched and straight chained olefin containing from about 10 to about 22 carbon atoms.

7. In the process of claim 5, the improvement wherein the molar ratio of maleic anhydride to olefin is about 0.8:1 to about 1.8:1. .

8. In a process for shaping processing of plastics, the improvement comprising adding to the plastic to be processed an effective amount of a lubricating agent compris-ing from about 10 to about 90% of an olefin-maleic anhydride copolymer having an average molecular weight from about 1,000 to about 30,000, wherein the olefin is selected from the group consisting of branched and straight chain olefins containing from about 8 to about 24 carbon atoms, and mixtures thereof, and the balance 1 or more members selected.
from the group consisting of aliphatic hydrocarbons with more than 12 carbon atoms, aromatic hydrocarbons, esters of fatty acids with more than 7 carbon atoms, wax esters, fatty alcohols with more than 7 carbon atoms, wax alcohols in mixture with neutral and/or basic lead salts, calcium, barium, lead carboxylates, zinc carboxylates, and tin thioglycolate stabilizers.