WO1989003853A1

WO1989003853A1 - Polycarbonate internal lubricants

Info

Publication number: WO1989003853A1
Application number: PCT/US1988/003433
Authority: WO
Inventors: Anthony J. O'lenick, Jr.
Original assignee: Gaf Corporation
Priority date: 1987-10-28
Filing date: 1988-10-06
Publication date: 1989-05-05
Also published as: AU2785789A

Abstract

This invention deals with the preparation, compositions, and application of complex esters which are useful in polycarbonate processing as internal lubricants.

Description

POLYCARBONATE INTERNAL LUBRICANTS

BACKGROUND OF THE INVENTION

1. Field of the Invention

2. Description of the Art Practices

It is known that esters of simple alcohols may be used for various purposes including polycarbonate processing. In U.S. Patent No. 3,784,595 issued January 8, 1974 to Schirmer et al polycarbonate molding compositions are shown which are based on the esters of a tr i hydr i c alcohol and a saturated aliphatic carboxylic acid. U.S. Patent No. 4,065,436 issued to Adelmann on December 1977 describes thermoplastic molding compositions containing a mold release agent which is an ester of a saturated aliphatic carboxylic acid having from 10 to 20 carbon atoms per molecule and an aromatic hydroxy compound containing from 1 to 6 hydroxyl groups.

It is also known from U.S. Patent No. 4,097,435 issued June 27, 1978 to Rawling et al that montanic acid ester waxes may be employed in polycarbonate molding compositions. U.S. Patent No. 4,131,575 issued December 26 , 1978 to Adelmann describes in combination with aromatic polycarbonates, mold release agents which are the esters of saturated aliphatic carboxylic acids with alcohol containing from 4 to 6 hydroxyl groups. The disclosures of U.S. Patent

No. 4,131,575 are also found in the related British Patent

No. 1,490,407 published November 2, 1977. U.S. Patent No.

4,143,024 issued March 6, 1979 to Adelmann et al describes aromatic polycarbonate based thermoplastic molding compositions utilizing as a mold release agent the ester of a saturated aliphatic carboxylic acid containing from 10 to

20 carbon atoms per molecule and an aromatic hydroxyl compound from having 1 to 6 hydroxyl groups.

General disclosures of polycarbonate technology are found in U.S. Patent No. 4,081,495 issued March 28, 1978 to Freitag et al. Similar general disclosures are also found in U.S. Patent No. 4,007,150 issued to Adelmann et al on February 8, 1977.

There are two different types of plastic lubricants. The mode of action and consequently the applications in which each type would be used differ considerably. External lubricants are insoluble in the polymer melt and as such have a tendency to form a mono-layer on the surface of the polymer. This results in a decrease in the friction between the metal and polymer. Such lubricants are referred to as mold release agents. Internal lubricants, on the other hand, are soluble in the polymer melt and as such have a tendency to promote flow of the polymer. These materials promote flow by reduction of internal stress and promotion of inter-molecular slippage.

Polycarbonate compared to other thermoplastics is relatively high in viscosity and requires higher processing temperatures. Consequently, the use of internal lubricants with polycarbonate is particularly important in applications in which non-injection molding occurs.

One of the large new growth areas for the use of polycarbonate in which internal lubrication is important is laser read compact recording discs. A superior grade of polycarbonate has been developed for this application and the presence of a mold release agent on the surface of the plastic has a very detrimental effect upon performance. The high performance internal lubricant of this invention are useful in this application.

Another new application area in which internal lubrication in polycarbonate is important is in the extrusion of polycarbonate sheets. In order to precision extrude these sheets to the tolerances required an effective internal lubricant agent is needed. Polycarbonate sheets are currently being evaluated as plastics for greenhouses. The esters of this invention are very useful in this application. The use of polycarbonate to make products safe for food contact like water and other beverage bottles, microwave wear, baby formula bottles, beer mugs, pitchers. and food storage containers requires specialty high performance internal lubricants. Here again the deposition of mold release agent on the surface of the bottle would be highly undesirable, but the presence of an effective amount of an internal lubricant is very desireable to increase process efficiency and minimize rejected product.

Lindner et al, U.S. Patent No. 4.425,458, issued January 10, 1984, teaches that specific guerbet alcohol diesters containing from 16 to 40 carbon atoms total in the guerbet alcohol molecule can be used as mold release agents in polycarbonate products. The Lindner esters are observed to migrate from the polycarbonate resin to the surface of the mold to effect release. As stated above, the external nature of the lubricant is based upon its relative insolubility in the polycarbonate. This insolubility results in the migration of the molecule to the polycarbonate / mold interface surface and results in mold release. The Lindner patent specifically states " The particular diacids with which the present (Lindner) invention is concerned are short chained acids containing less than 10 carbon atoms." (Col. 1 lines 64 - 66 U.S. Patent 84, 425, 458). This limitation occurs because the desired mold release properties depend upon insolubility of the lubricant in the polycarbonate.

Unexpectantly, we have found that using a higher molecular weight diacid, the resulting diesters are not effective mold release agents, but rather are internal lubricants and as such allow for the extrusion of polycarbonate sheets. This makes them suitable for the applications specified above.

To the extent that each of the foregoing patents is relevant to the present invention they are herein specifically incorporated by reference. Throughout the specification and claims, percentages and ratios are by weight, pressures are gauge and temperatures are Celsius unless otherwise noted.

SUMMARY OF THE INVENTION

A polycarbonate resin composition containing an effective amount of an internal lubrication agent which is a diester of a (a) guerbet alcohol and (b) a member selected from the source group consisting of a dicarboxylic acid containing from 12 to 20 carbon atoms and mixtures thereof and where the guerbet alcohol contains a total of from about 16 to 24 carbon atoms. DETAILED DESCRIPTION OF THE

INVENTION

The present invention describes the esters of a guerbet alcohol, and in particular esters of a guerbet alcohol and a difunctional acid. The particular esters of a guerbet alcohol which the present invention is concerned with are diacids from C 12 to C 20 and mixtures thereof which are reacted with approximately two moles of a guerbet alcohol to obtain the completely esterfied acid.

The guerbet alcohol portion of the present invention is particularly important in that polycarbonate resins have a high requirement for clarity as they are often used to form clear articles including safety glasses. Accordingly clarity is a particularly important aspect in obtaining a polycarbonate resin. Additionally, a substantial difficulty in the art has been to extrude polycarbonate sheets and other articles that do not rely upon mold release properties and to ensure that the polycarbonate resin is not adversely affected by the internal lubricant agent. The diesters of this invention fulfill this need.

The preparations of the diester may be accomplished by using as the acid component the diacid. The diesters are formed by reacting essentially one mole of the diacid with two moles of alcohol. This may be done such that the alcohol is present in an excess, which is subsequently stripped off under high vacuum and high temperature.

The diacid reaction with the alcohol may be catalyzed with a metal, conveniently with an organo-tin or titanium catalyst. The reaction thus proceeds when a small amount of heat is used to promote the reaction. Conveniently the reaction is conducted at from about 120 C to about 250 C, over a period of about 5 to 10 hours. The water which is produced as a by product of the reaction is then distilled off together with any excess starting alcohol and the product is recovered in a high degree of purity. When desired a nitrogen sparge and vacuum may be applied in order to collect the water and any additional starting alcohol. The condition for obtaining the product from the acid rather than the acid anhydride are substantially similar.

The polycarbonates with which the present diesters are effective mold release agents include homopol ycarbonates and copol ycarbonates which are based, for example, on one or more of the following bisphenols: hydroquinone, resorcinol, di hydroxydi phenyls, bis-(hydroxyphenyl)-al kanes, bis-(hydroxyphenyl)-eyeloalkanes, bis-(hydroxylphenyl)-sulphides, bis-(hydroxyphenyl)-ethers, bis-(hydroxylphenyl)-ketones, bis-(hydroxyphenyl)-sulphoxides, bis-(hydroxyphenyl)-sulphones and alpha, alpha-bis(hydroxyphenyl)-di isopropyl-benzenes, as wel l as their nuclear alkyiated and nuclear-halogenated compounds. These are further suitable aromatic dihydroxy compounds are described, for example, in U.S. Patent Nos. 3,028,365, 2,999,835, 3,148,172, 3,271 ,368, 2,991 ,273, 3,271 ,367, 3,280,078, 3,014,891 and 2,999,846, in German Offenlegungsschriften (German Publ ished Specifications) Nos. 1,570.703, 2,063,050, 2,063,052, 2,211,956, and 2,211 ,957, in French Patent Specification No. 1,561,518 and in the monograph "H. Schnel l , Chemistry and Physics of Polycarbonates, Interscience Publ ishers, New York, 1964".

Preferred bisphenols are those of the formula I shown below:

in which R is identical or different and denotes H, C1-alkyl , Cl or Br, and in which X is a bond, C₁C₈-alkylene, C₂-alkyl idene, C₅-C₁₅cycloalkylene, C₅-C₁₅-cycloalkyl idene, -SO- or formula II shown below:

Examples of these bisphenols are

4,4'-dihydroxydiphenyl, 2,2-bis-(4-hydroxyphenyl)-propane,

2,4-bis(4-hydroxyphenyl)-2-methylbutane,

1,1-bis-(4-hydroxyphenyl)-cyc1ohexane, a,a-bis(4-hydroxyphenyl)-p-diisopropylbenzene,

2,2-bis-(3-methyl-4-hydroxyphenyl)-propane,

2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, bis(3,5)-dimethyl-4-hydroxyphenyl)-2-methhylbutane,

1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane, a,a-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-di isopropyl-benzene , 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane and

2,2-bis(3,5-dibromo-4-hydroxyphyenyl)-propane.

Examples of particularly preferred bisphenols are: 2,2-bis-(4-hydroxyphenyl)-propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane, and 1,1-bis-(4-hydroxyphenyl)-cyclohexane.

Preferred aromatic polycarbonates are those, which are based on one or more of the bisphenols mentioned as being preferred. Particularly preferred copol ycarbonates are those based on 2,2-bis-(4hydroxyphenyl)-propane and one of the other bisphenols mentioned as being particularly preferred. Further particularly preferred polycarbonates are those based solely on 2,2-bis-(4-hydroxyphenyl)-propane or 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane.

The aromatic polycarbonates can be prepared in accordance with know processes, such as, for example, in accordance with the melt trans-esterification process from bisphenols and di phenyl carbonate and the two-phase boundary process from bisphenols and phosgene, as described in the above mentioned l iterature.

The aromatic high-molecular weight polycarbonates can be branched due to the incorporation of small amounts, preferably of between 0.05 and 2.0 mol % (relative to diphenols employed), of trifunctional or more than trifunctional compounds, especially compounds with three of more phenol ic hydroxyl groups.

Polycarbonates of this type are described, for example , in German Offen legungsschriften (German Published Specifications) Nos. 1,570,533, 1,595,762, 2,116,974 and 2,113,347; British Patent Specification No. 1,079,821 ; U.S. Patent No. 3,544,514 and German Patent Appl ication No. P25 00 092.4.

Some examples of compounds with three or more than three phenolic hydroxyl groups which can be used are phioroglucinol , 4,6-dimethyl-2,4,6-tri-(4hydroxyphenyl)-heptane-2, 4 , 6-d i me thyl -2 , 4 , 6- tr i - ( 4-hydroxyphenyl ) -he p tane ,

1,4,5-tri-(4-hydroxyphenyl)-benzene,

1,1,1-tri-(4-hydroxphenyl)-ethane, tri-(4-hydroxyphenyl)-phenylmethane,

2,2-bis-(4,4-bis-(4-hydroκyphenyl)-cyclohexyl)-propane,

2,4-bis-(4-hydroxyphenylisopropyl)-Phenol,

2,6-bis-(2-hydrox-5-methylbenzyl)-4-methyphenol,

2-(4-hydroxyphenol), 2-2,4dihydroxyphenyl)-propane, hexa(4-(4-hydroxyphenylisopropyl)phenyl) or thoterephthalic acid ester, tetra-(4-hydroxyphenyl)-methane and

1,4-bis-((4',4"-dihydroxytriphenyl)methyl)-benzene. Some of the other trifunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and

3,3-bis-(4-hydroxyphyenyl)-2oxo-2,3-dihydroindole.

The aromatic high-molecular polycarbonates should as a rule have mean weight-average molecular weights M of at least 10,000; especially of 10,000 to 200,000; preferably of 20,000 to 80000; determined by measuring the relative viscosity in CH₂Cl₂ at 25 degrees c. and a concentration of 0.5% by weight.

The thermoplastic polycarbonate compositions, using the lubricants of the present invention, find use in several high performance areas. Such examples of use for the polycarbonates of the present invention utilizing the internal lubricant agents include laser read comoact recording discs, precision extrusion of polycarbonate sheets for use in greenhouses and in products safe for food contact like water and other beverage bottles, microwave wear, baby formula, bottles, beer mugs, pitchers, and food storage containers and other similar high performance specialty applications.

The level of use of the diesters of this invention in the polycarbonate is from about 0.25% to about 1.0%; preferably from about 0.1% to about 0.25% by weight of the total polycarbonate compositions.

The following are suggested embodiments of present invention.

EXAMPLE 1

To 667.8 grams of a C ₁₆ guerbet alcohol ( sold commercially under the trade name Exxal 16 by Exxon Chemicals) is added 322.0 grams of dodecanediotic acid (CAS 693-23-2) under good agitation. 1.0 grams of of tin catalyst is added. The batch is heated to 140 to 200 C under a nitrogen sparge. Water begins to distill off at 140 C and continues. As the rate of water generation falls off vacuum is applied and the nitrogen sparge is turned off. 97 % of the theoretical water is removed and the acid value drops to below 5 mg KOH/gram. EXAMPLE 2

To 721.5 grams of a C₂₀ guerbet alcohol ( sold commercial ly under the trade name Exxal 20 by Exxon Chemicals) is added 278.5 grams of dodecanediotic acid (CAS 693-23-2) under good agitation. 1.0 grams of of tin catalyst is added. The batch is heated to 140 to 200 C under a nitrogen sparge. Water begins to distill off at 140 C and continues. As the rate of water generation falls off vacuum is appl ied and the nitrogen sparge is turned off. 97 % of the theoretical water is removed and the acid value drops to below 5 mg KOH/gram.

EXAMPLE 3

A suggested utilization of the guerbet diester dodecanedi oate as obtained in Example land 2 is conducted by using 0.12% by weight of the diester, and following the general procedure given at Column 6 of U.S. Patent. No. 4,065,436. By so following the general teachings of the aforementioned reference it will observed that the various diesters of the guerbet alcohols of the present invention give polycarbonates of high clarity and low volatility. Similar results are obtained by using the remaining esters of Example I.

Claims

Cl a i msWhat is claimed is:

1. A polycarbonate resin composition containing an effective amount of an internal lubrication agent which is a diester of a (a) guerbet alcohol and (b) a member selected from the source group consisting of a dicarboxylic acid containing from 12 to 20 carbon atoms and mixtures thereof and where the guerbet alcohol contains a total of from about 16 to about 24 carbon atoms.

2. The composition of claim 1 wherein the guerbet alcohol is a homoalcohol having 16 to 20 carbons and the diacid is dodecanediotic (a 12 carbon diacid).

3. The compositions of claim 1 wherein the guerbet alcohol contains a total of from about 20 to 34 carbon atoms.

4. The composition of claim 1 wherein the diester conforms to the following formula;

Wherein;

R is a derived from a guerbet alcohol having a total of between 16 and 20 carbon atoms.

R' may be the same or different than R and is derived from a guerbet alcohol having a total of between 12 and 36 carbon atoms.

5. The composition of claim 1 containing from about 0.025% to about 1.0% by weight of the diester.

6. The process which comprises adding an effective internal lubricating amount of the lubricating agent of claim 1 to a polycarbonate formulation prior to molding.

7. The process of claim 6 wherein said polycarbonate is molded into sheets.

8. The process of claim 6 wherein the polycarbonate is molded into laser read compact recording discs.

9. The process of claim 1 wherein said polycarbonate is molded into a container for a comestible or beverage product.