Thermoplastic resins having incorporated mold release agents

Details Thermoplastic resins having incorporated mold release agents Thermoplastic resins having incorporated mold release agents

1999-07-20

2003-04-22

Sergent, Rabon (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From reactant having at least one -n=c=x group as well as...

C524S379000, C524S385000, C524S386000, C524S389000, C524S765000, C524S766000, C528S075000, C528S076000, C528S080000, C528S084000, C528S085000

Reexamination Certificate

active

06552153

ABSTRACT:

The invention relates to thermoplastic polyurethanes having incorporated mold release agents. Mixtures of specific hydroxyl-terminating hydrocarbons are used as incorporable mold release agents.
It is necessary with many processes for producing plastics moldings to add to the plastics compositions lubricants or mold release agents to prevent adherence of the moldings to the mold wall and so improve formability and processability. The addition of mold release agents is indispensable in particular for the processing of thermoplastic polyurethanes or polyurethane ureas.
When producing moldings from polyurethanes, fatty acid derivatives are generally used as so-called “internal” release agents, that is to say they are contained in the molding composition. Such “internal” release agents for polyurethanes are described, for example, in DE-OS 23 07 589 and DE-OS 23 19 648. In use, the latter release agents have the disadvantage that after a few molding cycles the mold is observed to be contaminated with mold release agent which has bled through, necessitating interruption of the process.
The releasing effect of the release agents naturally takes place only at the product surface, to which they migrate more or less rapidly as a result of their incompatibility with the polyurethane. The releasing effect generally improves as the release agent content increases, with the possibility of higher concentrations leading to an undesirable grey bloom at the product surface, which becomes more pronounced during protracted storage. Where polyurethane granules have been stored for long periods before being further processed, the release agent concentration at their surface may become so high that an extruder may fail to take the product uniformly. Moreover, the release agent concentration at the surface in the freshly produced molding is low, such that the only effect of a large proportion of the added release agent is to form undesirable bloom. In the production of composite materials, exuded release agent may under some circumstances impair the other components of the materials.
Migration and hence exudation of mold release agents can be prevented if constituents which have a demolding effect are incorporated in the polymer. In DE-OS 34 36 163 condensation products of ricinoleic acid with glycols, and in EP-A 310 895 specific polyether polyols, are used as incorporable mold release agents. These incorporable release agents, however, either have a less pronounced releasing effect than conventional mold release agents or are not available commercially.
It has now been found that mixtures of specific hydroxyl-terminating hydrocarbons are highly suitable as incorporable mold release agents for thermoplastic polyurethanes and polyurethane ureas.
The present invention provides thermoplastic polyurethanes prepared by reacting the components
A) organic diisocyanate,
B) linear hydroxyl-terminating polyol having an average molecular weight M
n
of 500 to 5000 g/mol,
C) diol or diamine chain extender having an average molecular weight M
n
of 60 to 450 g/mol,
D) from 0.5 to 10 wt. %, with reference to the total product, of a mixture prepared from
a) 30≦x≦95 wt. % of hydroxyl-terminating hydrogenated polybutadiene of the formula (I)
HO—CH
2
—CH
2
—[—(CH
2
—CH
2
)
m
—{CH
2
—CH(CH
2
—CH
3
)}
n
—]—CH
2
—CH
2
—OH  (I)
wherein the ratio m
may be from 3:1 to 1.33:1, having an average molecular weight M
n
of 1000 to 10000 g/mol, a functionality of from 1.9 to 2.0 and a polymolecularity index M
w
/M
n
of from 0.8 to 1.4,
b) 0≦y≦70 wt. % of hydroxyl-terminating hydrogenated polybutadiene of the formula (II)
CH
3
—CH
2
—[—(CH
2
—CH
2
)
p
—{CH
2
—CH(CH
2
—CH
3
)}
q
—]—CH
2
—CH
2
—OH  (II)
wherein the ratio p/q may be from 3:1 to 1.33:1, having an average molecular weight M
n
of 500 to 10000 g/mol, a functionality of from 0.9 to 1.0 and a polymolecularity index M
w
/M
n
of from 0.8 to 1.4,
c) 0≦z≦70 wt. % of hydroxyl-terminating block copolymer prepared from polyisoprene and poly(co-ethylene-butylene-styrene), having a styrene unit content of approximately 40 wt. %, an average molecular weight M
n
of 500 to 10000 g/mol, a functionality of from 0.9 to 1.0 and a polymolecularity index M
w
/M
n
of from 0.8 to 1.4, and a ratio ethylene/butylene in the range of 3:1 to 1.33:1, having 5≦(y+z)≦70,
wherein the molar ratio of the NCO groups in A) to the groups capable of reacting with isocyanate in B), C) and D) is from 0.9 to 1.2.
Aliphatic, cycloaliphatic, araliphatic, heterocyclic and aromatic diisocyanates such as are described in Justus Liebigs Annalen der Chemie [Annals of Chemistry], 562, pp. 75-136, are, for example, considered as organic diisocyanates A).
The following may be named as individual examples: aliphatic diisocyanates such as hexamethylene diisocyanate, cycloaliphatic diisocyanates such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate and 1-methyl-2,6-cyclohexane diisocyanate, and the corresponding isomer mixtures, 4,4′-dicyclohexylmethane diisocyanate, 2,4′-dicyclohexylmethane diisocyanate and 2,2′-dicyclohexylmethane diisocyanate, and the corresponding isomer mixtures, aromatic diisocyanates such as 2,4-tolylene diisocyanate, mixtures of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate and 2,2′-diphenylmethane diisocyanate, mixtures of 2,4′-diphenylmethane diisocyanate and 4,4′-diphenylmethane diisocyanate, urethane-modified liquid 4,4′-diphenylmethane diisocyanates and 2,4′-diphenylmethane diisocyanates, 4,4′-diisocyanato diphenylethane-(1,2) and 1,5-naphthalene diisocyanate. The following are preferably used: 1,6-hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate isomer mixtures having a 4,4′-diphenylmethane diisocyanate content of >96 wt. % and in particular 4,4′-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate. The diisocyanates named may be used in either single or intermixed manner. They may also be used together with up to 15 wt. % (with reference to the total quantity of diisocyanate) of a polyisocyanate, for example triphenylmethane-4,4′,4″-triisocyanate or polyphenyl polymethylene polyisocyanates.
As component B), linear hydroxyl-terminating polyols having an average molecular weight M
n
of 500 to 5000 g/mol are used. These frequently contain small quantities of non-linear compounds by reason of their production process. For this reason reference is also commonly to “substantially linear polyols”. Polyester diols, polyether diols, polycarbonate diols or mixtures thereof are preferred.
Suitable polyether diols may be prepared by reacting one or more alkylene oxides having 2 to 4 carbon atoms in the alkylene radical with an initiator molecule containing two bonded active hydrogen atoms. Examples of alkylene oxides which may be named are ethylene oxide, 1,2-propylene oxide, epichlorohydrin and 1,2-butylene oxide and 2,3-butylene oxide. Ethylene oxide, propylene oxide and mixtures of 1,2-propylene oxide and ethylene oxide are preferably used. The alkylene oxides may be used singly, alternately or as mixtures. Examples of initiator molecules which are considered are water, aminoalcohols such as N-alkyl diethanolamines, for example N-methyl diethanolamine, and diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol and 1,6-hexanediol. Mixtures of initiator molecules may optionally also be used. Suitable polyether diols are furthermore the hydroxyl group-containing polymerization products of tetrahydrofuran. Trifunctional polyethers may also be used in quantities of from 0 to 30 wt. %, with reference to the bifunctional polyethers, the maximum quantity whereof being, however, such that a product results which is thermoplastically processable. The substantially linear polyether diols have average

Affiliated with

Also associated with

Rating

Thermoplastic resins having incorporated mold release agents does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Thermoplastic resins having incorporated mold release agents, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic resins having incorporated mold release agents will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3108333