Siloxane block copolymers having linked siloxane blocks

Details Siloxane block copolymers having linked siloxane blocks Siloxane block copolymers having linked siloxane blocks

2000-04-12

2004-05-04

Lu, Caixia (Department: 1713)

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

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C556S444000, C556S445000, C528S027000, C528S035000

Reexamination Certificate

active

06730749

ABSTRACT:

The invention relates to novel siloxane block copolymers having linked, different siloxane blocks and the use thereof.
According to the prior art, there is a large number of surface-active siloxane block copolymers which are used in a wide range of industrial applications. These may be methylpolysiloxanes (cf. DE-C-25 33 074) as well as (pseudo)haloalkyl-substituted siloxanes (cf. DE-C-36 26 297, U.S. Pat. No. 3,952,038 or DE-A-24 02 690), which, for example, are used as cell regulators in highly resilient, cold-curing polyurethane foams. A wide range of silicone-polyether copolymers and their use as surface-active substances are also known, as described, for example, in the following patents by way of example:
DE-C-15 70 647: Chloropolysiloxanyl sulfates are reacted with mixtures of alkylene adducts which consist of
from 50 to 96 OH-equivalent percent of polyalkylene glycol monoethers which consist of ethylene oxide and propylene oxide units and contain from 40 to 70% by weight oxypropylene units and have a molecular weight of from 1000 to 3000, whose hydroxyl groups are preferably secondary, and
from 5 to 50 OH-equivalent percent of alkylene oxide adducts of polyvalent hydroxyl compounds having a molecular weight of from 130 to 3500, whose polyalkylene glycol components consist of ethylene oxide and/or propylene oxide units and have an OH equivalent weight of up to 1750 and whose hydroxyl groups are preferably secondary,
the ratios being chosen so that not more than 1.4, preferably from 1.05 to 1.2, OH equivalents are present per acid equivalent of the chloropolysiloxanyl sulfate.
DE-C-16 94 366: Polysiloxane-polyoxyalkylene block copolymers whose polysiloxane block has a composition known per se but whose polyalkylene block consists of
from 25 to 70% by weight of a polyoxyalkylene having an average molecular weight of from 1600 to 4000 and an ethylene oxide content of from 20 to 100% by weight, the remainder being propylene oxide and optionally higher alkylene oxides, and
from 30 to 75% by weight of a polyoxyalkylene having an average molecular weight of from 400 to 1200 and an ethylene oxide content of from 65 to 100% by weight, the remainder being propylene oxide and optionally higher alkylene oxides,
are used as foam stabilizers.
DE-A-25 41 865: The polysiloxane-polyoxyalkylene block copolymers are defined, with respect to their polyoxyalkylene blocks, in such a way that one polyoxyalkylene block has an average molecular weight of from 900 to 1300 and comprises from 30 to 55% by weight of ethylene oxide, the remainder being propylene oxide, and the other polyoxyalkylene block has an average molecular weight of from 3800 to 5003 and comprises from 30 to 50% by weight of ethylene oxide, the remainder being propylene oxide.
EP-A-0 275 563: The block copolymer described in this patent application comprises three different polyoxyalkylene blocks, namely a block which contains from 20 to 60% by weight of oxyethylene units, with a molecular weight of from 3000 to 5000, a further block having from 20 to 60% by weight of oxyethylene units and a molecular weight of from 800 to 2900 and a third block comprising only polyoxypropylene units and having a molecular weight of from 130 to 1200.
The patent literature furthermore describes siloxane block E-E -copolymers which are used as emulsifiers and in which both polyoxyalkylene groups and long-chain alkyl groups are bonded to linear polysiloxanes (cf. for example U.S. Pat. No. 3,234,252, U.S. Pat. No. 4,047,958 or DE-C-34 36 177).
Further patents (e.g. U.S. Pat. No. 5,136,068, EP-A-0 381 318 and EP-A-0 529 847) describe surface-active siloxane block copolymers for use as emulsifiers, in which polyoxyalkylene radicals and long-chain alkyl radicals are bonded to the polysiloxane and an additional linkage of the siloxane block copolymer via a divalent organic radical is present. The feature of the siloxane block copolymers described is that in all cases identical siloxane blocks are linked to one another by reaction of SiH groups with, for example, diolefins, divinylbenzene or 1,3-divinyltetramethyldisiloxane.
In spite of the large number of siloxane block copolymers thus obtainable, the large number of fields of use for these active substances, for example
as additives for solvent-containing and also low-solvent finishes, surface coatings and pastes,
for coating textiles and paper (tissues),
as starting materials for crosslinking reactions,
as antifoams,
as emulsifiers,
as additives in cosmetic formulations,
as stabilizers for the wide field of PU foam production (on the one hand, a large number of possible polyurethane foam types, such as, for example, flexible foam, rigid foam, ester foam, cold-curing foam, packaging foam, flame-laminatable foam, molding foam, integral foam, etc., and, on the other hand, more modern foaming techniques, such as variable pressure foaming, foaming with inert gases under pressure or forced cooling processes, for example ENVIRO—CURE, from CRAIN INDUSTRIES),
makes it necessary to find structures which are further improved.
Surprisingly, it has now been found that the linkage of different siloxane blocks in one molecule has surprising effects in various application tests. According to the teaching of the present invention, different siloxane copolymer blocks (different based on the modifying radicals on the siloxane and/or the structure of the siloxane segment) can be linked to one another in a simple manner via coupling agents, and novel siloxane block copolymers in which the linked siloxane copolymer blocks differ, for example, in their polarities, in their hydrophilic/hydrophobic balance or in proportions of reactive groups can thus be synthesized in a controlled manner.
The present invention thus relates to siloxane block copolymers of the general average formula:
where the radicals and indices have the following meaning:
A=radical R
1
, radical E or a radical of the formula IIa
 or a radical of the formula IIb
B=radical of the formula IIa or IIb
Y=radical y
1
or radical Y
2
,
D=radical of the formula
R
1
=an alkyl radical having 1 to 30 carbon atoms, a substituted alkyl radical, an optionally substituted aryl radical or an optionally substituted alkaryl radical, where however at least 80% of the radicals R
1
are methyl groups,
a has a value from 3 to 200,
b has a value from 0 to 50,
c has a value from 0 to 10,
d has a value from 0 to 5 and
e has a value from 0 to 4,
where the values for a, b, c, d and e in the individual segments Z of the radicals A, B and D may be different,
E=radical which
a) is a radical of the general formula
—R
f
2
—O—(C
m
H
2m
O—)
n
R
3
in which
R
2
is a divalent alkyl radical which may also be branched and
f has a value of 0 or 1,
m has a value of, on average, from 2 to 4,
n has a value from 0 to 100 and
R
3
is a hydrogen radical, an optionally substituted alkyl radical having 1 to 6 carbon atoms, an acyl radical or a —O—CO—NH—R
4
radical in which R
4
is an optionally substituted alkyl or aryl radical, and/or
b) has the meaning of an epoxy-functionalized alkyl substituent optionally containing hetero atoms, and/or
c) has the meaning of a mono-, di- and trihydroxyalkyl substituent which may also be aromatic or branched and partially or completely etherified or esterified, and/or
d) has the meaning of a halogen- or pseudohalogen-substituted alkyl, aryl or aralkyl radical which optionally may also be branched,
X=a polyvalent organic radical, with the proviso that at least one radical of the formula IIa or IIb is present in the molecule and at least two of the segments Z are different.
It is also possible to use different substituents in combination, as described, for example, for polyether substituents in DE-C-42 29 402. The substituents may optionally differ from one another, for example in their molar mass, in the case of polyethers possibly in their terminal group R
3
or the proportions of the monomers used, in the type of monomers, etc.
X is a polyvalent organic radical (valency=2+e). The radical X is

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