Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Patent
1994-03-30
1997-05-27
Seidleck, James J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
528423, 528503, 525 38, 525 36, 525 43, 525 44, C08G 6926
Patent
active
056333412
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/CH93/00182 filed Jul. 19, 1993.
SUBJECT OF THE INVENTION
The invention concerns crosslinkable, two component compositions and methods of their manufacture and use.
STATE OF THE ART
Liquid polymers or copolymers containing acid anhydride groups are valuable raw materials for the formulation of reactive adhesives, sealants, coatings and casting compounds. The acid anhydride groups can be distributed statistically or randomly in the molecule, or in the terminal position. The introduction of the acid anhydride groups can be achieved through copolymerization, through reaction with terminal reactive groups, through subsequent addition of unsaturated anhydrides onto individual or conjugated double bonds or by means of graft reactions.
In EP 048 128 and DE 3 830 895, the crosslinking of polymers containing acid anhydride groups with polyhydroxyl compounds has been suggested. The speed of crosslinking can be controlled through adding tertiary amines. The strength of the polymers containing anhydrides, crosslinked using polyhydroxyl compounds, and mainly the lower tear strength, restricts the area of application of the crosslinked compositions.
High strength of the crosslinked products is expected through reaction of polymers containing acid anhydride groups with polyamines. Di- or polyamines are recommended as a crosslinker in patent specifications EP 73 022 and EP 282 184, amongst others. Polymers react extremely rapidly with polymers containing acid anhydride groups, and large volumes are only able to be worked with difficulty in view of the very short work time. In addition, some aliphatic and aromatic amines are toxicologically suspect.
In order to cope with this difficulty, high molecular weight or polymeric polyamines are used. With the decrease in the concentration of the amino groups, the strength of the crosslinkage products will simultaneously decline.
In patent specifications DE 2 610 406, DE 853 477, EP 259 172 and EP 284 953, crosslinking of polymers containing acid anhydride groups with blocked polyamines has been suggested. Blocked polyamines containing ketimine, aldimine or oxalane groups require moisture or water in order to release the amines. By this reaction, aldehydes or ketones will be released, which must be diffused out of the crosslinked products. For this reason, these crosslinkers are in practice only suitable for thin layers.
In the patent specification DE 758 222, crosslinking of the liquid polymer containing anhydride with a complex of 4,4'-diaminodiphenylmethane and sodium chloride has been suggested. The disadvantage here is that higher temperatures must be used for crosslinking, and that the final product contains salt, for which reason application will be very restricted, mainly for reasons of corrosion protection.
There is a large demand, however, for shrink free elastic compositions which crosslink at room temperature, for casting, sealing, bonding and coating, and mainly for those with low toxicity.
The task which forms the basis of the invention is to make available new crosslinking agents, which react in ambient conditions with liquid polymers containing anhydride groups, the crosslinked products of which are distinguished by considerably higher mechanical strength, combined with initial tear strength and tear propogation resistance.
This purpose is fulfilled by the crosslinkable, two component composition according to claim 1 and the method of its manufacture according to claim 14. It is particularly solved by two component compositions of polymers containing acid anhydride groups and sterically hindered aromatic amines, diamines or polyamines as crosslinking agents. Steric hindrance means that the amino group is substituted in neighbouring or ortho positions.
The following are suitable as substituents: linear or branched alkyl groups with 1-4 C-atoms, such as methyl-, ethyl-, propyl-, isopropyl-, butyl-, sec.butyl- and tert.butyl groups.
The following are preferable: 1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,4-diaminoben
REFERENCES:
patent: 4145321 (1979-03-01), Lee
patent: 4497663 (1985-02-01), Fisher et al.
patent: 5071937 (1991-12-01), Potter et al.
patent: 5244946 (1993-09-01), Guest et al.
patent: 5376710 (1994-12-01), Slongo et al.
Copy of the International Search Report.
Ciba Geigy Corporation
Crichton David R.
Seidleck James J.
Truong Dvc
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