Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Patent
1998-09-14
2000-12-12
Hampton-Hightower, P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
528310, 528312, 528322, 528323, 528326, 528332, 528335, 528336, 524600, 524606, C08G 6902, C08G 6904, C08G 6916, C08G 6936
Patent
active
061600806
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a polyamide comprising macromolecular chains with a different chemical structure and to a process for its manufacture, as well as to compositions containing it.
It relates more particularly to a polyamide composed of polymer units exhibiting a star configuration and, optionally, linear polymer units.
The use of linear aliphatic or semiaromatic polyamides as plastic forming the matrix of a composition intended to be shaped has been known for a very long time. In order to improve the mechanical properties of these plastics, these compositions comprise fillers in the powder or fibre form, such as, for example, glass fibres. However, these fillers result in an increase in the viscosity of the composition in molten medium, or more generally limit the rate of flow of the composition when the latter is injected into a mould. In order to obtain correct filling of moulds or a rapid moulding rate, it is necessary to limit the amount of filler in the composition. Thus, the maximum concentrations allowable are generally in the region of 40% by weight.
Another consequence of this slow or difficult flow of compositions containing or not containing fillers is a poor surface appearance of the moulded articles. This is because the fillers, such as fibres, are visible at the surface of the article. In order to overcome this problem, provision has been made for the addition of an amorphous polymer or a polymer exhibiting slower crystallization kinetics to the semi-crystalline matrix, in particular when the latter is a poly(hexamethylene adipamide).
Provision has also been made to use low molecular weight polymers in order thus to improve the filling of the moulds, such as, for example, in U.S. Pat. No. 5,274,033. However, the mechanical properties of the material are reduced.
Polyamides exhibiting a star structure obtained with polyfunctional aromatic compounds are described in U.S. Pat. No. 5,346,984. However, these polymers exhibit an entirely star-type structure and have low molecular weights. These two characteristics limit their use in the manufacture of moulded articles or in industrial and technical applications, because their mechanical properties are inadequate.
One of the aims of the present invention is to overcome these disadvantages by providing a polyamide exhibiting a high fluidity in the molten state and comparable or improved mechanical properties with respect to a conventional linear polyamide. This polyamide can be used as element or component of a polymer matrix in a composition containing a high level of filler. Such a composition has a good ability to be injected in the manufacture of moulded articles.
To this end, the invention provides a polyamide composed of a mixture of macromolecular chains of following formulae I and II: ].sub.m (I) ##STR1## in which:
Y is the ##STR2## radical when X and Z represent the ##STR3## radical,
Y is the ##STR4## radical when X and Z represent the ##STR5## radical,
A is a covalent bond or an aliphatic hydrocarbon radical which can comprise heteroatoms and which comprises from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms,
R.sub.2 is a branched or unbranched aromatic or aliphatic hydrocarbon radical comprising from 2 to 20 carbon atoms,
R.sub.3 and R.sub.4 represent hydrogen or a hydrocarbon radical comprising a ##STR6## group,
R.sub.5 represents hydrogen or a hydrocarbon radical comprising from 1 to 6 carbon atoms,
R.sub.1 is an aromatic or aliphatic, linear or cyclic, hydrocarbon radical comprising at least 2 carbon atoms and which can comprise heteroatoms,
m is an integer between 3 and 8 (inclusive)
n is a number between 100 and 200 (inclusive)
p is a number between 100 and 200 (inclusive).
According to another preferred characteristic of the invention, when the R.sub.1 radical is not an aromatic radical, the ratio by mass of the weight of polymer chains of formula I to the total weight of polymer chains of formulae I and II is between 0.10 and 1.
When R.sub.1 represents an aromatic radical, the above ratio by mass is less th
REFERENCES:
patent: 3549601 (1970-12-01), Fowell
patent: 5346984 (1994-09-01), Hasegawa et al.
Cucinella Antonino
Di Silvestro Giuseppe
Guaita Cesare
Speroni Franco
Zhang Haichun
Hampton-Hightower P.
Nyltech Italia
LandOfFree
Polyamide, method for its manufacture and compounds containing i does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polyamide, method for its manufacture and compounds containing i, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polyamide, method for its manufacture and compounds containing i will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-218812