CA1072565A - Resinous terpene maleimide and process for preparing same - Google Patents

Abstract

5,977 A B S T R A C T

There are provided resinous terpele maleimides use-ful as tackifiers for elastomers and prepared by reacting at temperatures between 140°C. and 200°C. substantially equi-molar amounts of (a) non-conjugated monocyclic terpenes or mixtures thereof and (b) maleic acid anhydride in the pres-ence of from 0.05% to 0.15% iodine, based on the weight of the terpene, recovering a mixture of not less than 85% mono--adduct and not more than 15% di-adduct of terpene maleic adduct, further reacting said adduct mixture with stoichio-metric amounts of a polyamine, and recovering terpene maleim-ide having a number average molecular weight between about 500 and about 600.

Description

25,977 ~Z565 The present invention relates to novel resin-ous terpene maleimides, a process for preparing the same, and the novel utilization of the same as tackifiers for polar elastomers. More particularly, it relates to ter-pene maleimides prepared from a mixture of terpene maleic anhydride adducts containing not less than 85~ terpene maleic anhydride mono-adduct and not more than 15% ter-pene maleic anhydride di-adduct.
It is important to emphasize that the terpene maleic anhydride adducts are mixtures of the possible adducts thus resulting in a liquid or viscous glassy residue rather than the crystalline materials produced from pure conjugated terpenes and maleic anhydride.
These adduct mixtures are later used to prepare imide derivatives which are resinous materials and have no tendency to crystallize because of their varied struc-

- 2 -1 ~7~

tures. Although terpene maleic adducts are known (United States 2,208,321, lines 10-23), control of their composition is not.
It is known that polyimides can be variously prepared from dian-hydrides and diamines. However, as far as can be determined, resinous imides of terpene-mono anhydride adducts and diamines yielding terpene-imide-imide-terpene con~iguration are not known. If the latter can be attained, such would amount to a substantial advance in the art.
It has been unexpectedly found that soluble, resinous terpene maleimides can be prepared in a straight-forward manner by reacting terpene maleic anhydride adducts containing not less than 85% mono-adducts with a diamine at elevated temperatures. The resultant terpene maleimide having primarily a terpene-imide-imide-terpene configuration finds utility, particularly, as a tackifier for polar elastomers.
According to the invention, substantially stoichiometric amounts of terpene maleic anhydride adduct and a diamine, such as ethylene diamine or trimethylene diamine or phenylene diamine are reacted at elevated temperatures in the ~ange of from about 140C to about 2LIOC so as to re-cover a resinous terpene maleimide.
Thus the present invention provides a process for preparing terpene maleimide resins which comprises: reacting attemperatures between lLl0C and 200C substanitally equimolar amounts of (a) a non-conjugated terpene or mixtures thereof and (b) maleic acid anhydride in the presence of from 0.05%
to 0.15% iodine based on the weight of the terpene, recovering a mixture of not less than 85% mono-adduct and not more than 15% di-addict of terpene maleic adducts, further reacting said adduct mixture with stoichiometric amounts of an aliphatic or aromatic diamine, and recovering terpene male-imide having an average molecular weight bet,ween about 500 and about 600.
By the term resinous, as that term is employed herein, is meant that the subject maleimides when added to an elastomeric composition impart permanent tackiness thereto as can be appreciated from the illustrative examples which are included herein.

In general, the terpene maleic anhydride ad-i"``s s~'~
1 duct reactant can be prepared by reacting equimolar amounts of a non-conjugated terpene, such as limonene, terpinolene, 1,4-para-methadiene, terpineol, 1,4-cineole, or 1,8-cineole, or mixtures of the same, with maleic anhydride at temperatures ranging from about 175C. to about 200~C. in the presence of from about 0.05~ to 0.15 iodine, based on the weight of the terpene. Resultant adduct comprises a mixture of at least 85% mono-adduct.
The choice of the temperature and iodine range results in the economic production of the mono-adduct with a controllably small percentage of di-adduct.
Control of the composition of the adduct allows produc-tion of the desired resinous imide derivative.
Additionally, the terpene-maleic anhydride ad~uct, in spite of preparation from these widely dif-ferent terpene feed stocks enumerated, shows essentially the same gel-phase chromatographic size distribution.
The chosen iodine level and temperature apparently es-tablish approximately the same equilibrium mixture of conjugated terpenes which in turn react with the maleic anhydride to form their adducts of uniform composition.
Exemplary of the diamines which can be employ-ed are trimethylene diamine, ethylene diamine, phenylene diamine, toluene diamine, as well as diethylene triamine.
To facilitate a further understanding of the invention, the following examples are presented primar-ily for purposes of illustrating the more specific de-tails thereof. The invention is not to be limited there-by except as defined in the instant claims. Unless otherwise stated, the parts are by weight.

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1 EXAMPLE__l A small amount of terpene maleic anhydride adduct (previously prepared) was dissolved in a small amount of xylene and added to the reactor. This mix is used to provide heat transfer for starting the con-tinuous addition of the other ingredients. The mix is heated to 200C. effecting reflux and is followed by addition of iodine (1.1 par*s to the kettle). Over a two-hour period 906 parts of limonene and 588 parts of maleic anhydride and xylene are added continuously.
The xylene is added at a metered rate such that the ket-tle temperature remains at 200C. and some reflux is maintained at all times~ The reaction between the ter~
pene and the maleic anhydride is exothermic and the heat of the reaction is dissipated at the condenser. The condensate goes through a separator and then is returned to the top of the condenser. Some water may be removed during this reaction if the maleic anhydride contains some maleic acid or if there are any cineoles in the terpene fraction these are dehydrated to dipentene in the presence of the iodine catalyst. The xylene reflux serves to dissipate the heat of the reaction and also flushes any maleic anhydride vapors or sublimates back to the reactor. After the ingredients are added, the kettle is held for an additional two hours at 200C.
~leat is withdrawn and the mix cooled to 100C.
There is recovered a yield of 1360 parts ~91%
yield) of a maleic anhydride terpene adduct mixture as a pale yellow liquid. Analysis of this adduct by gel permeation chromatography showed 95% mono-adduct and 5~;~

1 about 5~ of di-adduct.
The imide product having a terpene-imide--imide-terpene type configuration, is next prepared by reacting 588 parts of the adduct mixture with 77 parts of ethylene diamine in 200 parts (by volume) of xylene.
The ethylene diamine is slowly added to the adduct at 140C. and any product water is removed as an azeotrope.
When the addition of the diamine is complete, the kettle temperature is slowly raised to 2~0C. to facilitate removal of water and solvent. After reachin~ 240C.
kettle temperature, the product is vacuum steam stripped at 50 mm pressure for 3 hours to remove any volatile oils. The stripped resin is then cooled and drummed or alternatively flaked and bagged.
The product which is a resinous terpene male-imide possesses the following properties:
Softening Point (C.) 88 ~cid Number Number Average Molecular Weight 533 Cloud Point* C. 159 * Cloud point is determined by admixing 2.5 parts of resultant resin with 10 parts of a l:l mixture of Elvax 150~ (33% vinyl acetate - ethylene copolymer) and Ceratak~
~(microcrystalline wax m.p. 165F.), melting to a clear melt, and allowing the melt to cool slowly until it clouds.

Repeat Example 1 except 147 parts of _-phen-ylene diamine in place of ethylene diamine, and 5 parts of ~-toluene ~ulfuric acid were added when the temper-ature reached 200C.

~ 565 1 S.P. - 129C.
Acid # - 3 Cloud Point-~300C.
EX~PLE 3 Repeat Example 1 except 91 parts 2,~-diamino-toluene were used with 33 parts ethylene diamine in place of 77 parts o~ ethylenediamine.
S.P. - 114C.
Acid #
10 Cloud Point* - 258C.

The process of Example 1 is repeated in every detail except that the terpene fraction therein is sub-stituted by 930 parts of a terpene fraction comprising abaut ~0~ terpinolene, 25% dipentene, 30% 1,4-cineole and the balance being terpene hydrocarbons and terpene alcohols.

The process of Example 1 is repeated in every detail except that 97% limonene is substituted for the terpene fraction mixture therein. There is obtained a limonene maleic anhydride adduct ln a yield of about 92% having more than 95% mono adduct in said mixture and being a light yellow li~uid.

_ _ , The terpene imides as prepared by the proced-ure of Examples 1 and 2 are compounded with additives into three hot melt formulations utilizing Elvax~ 250 (28% vinyl acetate - 72~ ethylene copolymer); Elvax~

150 (33~ vinyl acetate - 67~ ethylene copolymer); Elvax~

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1 40 (40% vinyl acetate - 60% ethylene copolymer);
Shellwax~ 300 (paraffin wax mp = 159F.) The formula-tions are tabularized below:
Table I

Formulations A B X
Parts by Parts by Parts by Compositions Wt. Wt. Wt.

Terpene Imide of Ex. 1 40 -- 40 Terpene Imide of Ex. 2 -- 40 --Elvax~ 250 40 -- --Elvax~ 150 -- 40 --Elvax~ 40 -- -- 40 Shellwax~ 300 20 20 20 The formulas (A, B, and C above) are employed at a coating on one (1) of a plurality of substrates (i.e., substrates 1 below) which are then sealed to a second substrate 2 at 225F. for a 0.3 sec. under ten pounds per square inch (10 psi) pressure. The peel strength is next determined by Instron testing in ounces per inch according to pressure sensitive tape Council method (PSTC - 1). The results are tabularized below:

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à5 Q C ) ~D I ~ O
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~H
~rl a _ ,~
E~
N m u~ ~ ~ ~ ~r ~ ~
O ~ (~~fl ~1 -1 N ~ ~
--,~
,C; ~
~1 S~
~ O
V~
a~ ~ ~

H¦
H

a)l ~1 ~1 ~1 a~
a~
~ 0~ ~ ~
~ ''I S~ O ~ rl .,1 ~ rd ~
~ O ~ ~1 U~ ~
S~
(a R
U~

G) ~ 565 1 Advantageously, the low-molecular weight ter-pene imide resins prepared in accordance with the pro-cess of the present invention possess the following overall properties:
Softening Point, C 70-110 Color (Gardner, 50/50 Toluene) 1-4 Acid Number 1-10 Molecular Weight 500-600 Appearance Clear, light-amber resin Cloud Point* C. 140-200 Specific Gravity/ 25/25C. 1.152 Toluene Insolubles, %0.018 * Cloud Point as determined above.

The terpene imide resins are soluble in aro-matic hydrocarbons, chlorinated hydrocarbons, esters, ketones, ethers, and alcohols, but insoluble in aliphatic hydrocarbons. Due to their molecular weight and compat-ibility as shown by cloud point of about 160C., the resins of the present invention find utility as tacki-fiers in polar formulations.

Claims (8)

1. A process for preparing terpene maleimide resins which comprises: reacting at temperatures be-tween 140°C. and 200°C. substantially equimolar amounts of (a) a non-conjugated terpene or mixtures thereof and (b) maleic acid anhydride in the presence of from 0.05%
to 0.15% iodine based on the weight of the terpene, re-covering a mixture of not less than 85% mono-adduct and not more than 15% di-adduct of terpene maleic adducts, further reacting said adduct mixture with stoichiometric amounts of an aliphatic or aromatic diamine, and recover-ing terpene maleimide having an average molecular weight between about 500 and about 600.

2. The process according to Claim 1 wherein the terpene is terpinolene.

3. The process according to Claim 1 wherein the terpene mixture comprises terpinolene and cineole.

4. The process according to Claim 1 wherein the terpene is limonene.

5. The process according to Claim 1 wherein the iodine added is 0.12%, based on the weight of the terpene reactant.

6. The process according to Claim 1 wherein the diamine is ethylene diamine.

7. The process according to Claim 1 wherein the diamine is trimethylene diamine.

8. A resinous terpene maleimide having an average molecular weight ranging from about 500 to 600 and softening points ranging fxom 70°C. to 110°C.