Polyorganosiloxane mixtures for treating fibre materials

Details Polyorganosiloxane mixtures for treating fibre materials Polyorganosiloxane mixtures for treating fibre materials

2002-10-17

2004-03-16

Dawson, Robert (Department: 1712)

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

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C524S837000, C525S477000, C525S478000, C252S008610, C252S008620, C252S008630, C528S031000, C528S038000

Reexamination Certificate

active

06706812

ABSTRACT:

This invention relates to specific polysiloxane mixtures, to a process for preparing these mixtures and also to the use of such mixtures for treating fiber materials, especially nonwovens.
It is known to use polyorganosiloxanes containing Si—H groups for finishing, including hydrophobicizing, fiber materials. The treatment of nonwovens with polysiloxanes is also known. It is further known that polyorganosiloxanes containing Si—H groups can react with water, in which case the Si—H groups are converted into Si—OH groups by detachment of hydrogen. Si—H groups also react with other compounds containing OH groups, including for example with polyorganosiloxanes having Si—OH groups, in which case the detachment of hydrogen gives rise to new Si—O— bonds, especially Si—O—Si. When fiber materials are treated with a mixture of products containing siloxanes with Si—H groups and siloxanes with Si—OH groups in the absence of a catalyst, unsatisfactory water-repellent properties are obtained. But even the use of a customary crosslinking catalyst does not ensure that all such mixtures will provide good results.
Polyorganosiloxanes based on polyorganohydrosiloxanes, &agr;,&ohgr;-dihydroxypolydiorganosiloxanes, optionally amino-functional silicon compounds and also catalysts are also known and described for example in EP-A 767 217. According to this EP-A, the polymers are prepared using three different dihydroxypolysiloxanes having different molecular weights. The use of amino-functional monoalkoxy- or dialkoxy-silanes is not described. The reaction is carried out in the presence of a condensation catalyst. Polyorganosiloxanes based on polyorganohydrosiloxanes, &agr;,&ohgr;-dihydroxypolydiorganosiloxanes and amino-functional alkoxysilanes and their use for finishing fiber materials are likewise known and described for example in EP-A 702 106. Here too the reaction is carried out in the presence of a crosslinking catalyst. A chemical reaction between the components mentioned is not carried out prior to application to the fiber material. Further components take part in the reaction on the fiber material.
Also known are foamable polyorganosiloxane compositions. They are obtainable by mixing organosiloxane rubbers, polyorganohydrosiloxanes, &agr;,&ohgr;-dihydroxypolydiorganosiloxanes and amino-functional alkoxysilanes and optionally further starting materials; this is described in EP-A 841 366 for example. The starting materials used are block copolymers containing R SiO
1.5
units, i.e. Si atoms to which 3 oxygen atoms are attached.
U.S. Pat. No. 4,177,176 describes compositions for the treatment of fiber materials. The compositions contain a modified &agr;,&ohgr;-dihydroxypolydimethylsiloxane which contains amino groups and is preparable from unsubstituted &agr;,&ohgr;-dihydroxypolydimethylsiloxane by reaction with an amino-containing alkyldialkoxysilane. The compositions further contain a siloxane having Si—H bonds. The amino-functional siloxane and the siloxane containing Si—H bonds are present as a mixture; compositions including a product formed by a chemical reaction between the two siloxanes mentioned are not mentioned in this US reference.
The prior art polysiloxane compositions have disadvantages. Without a partial chemical reaction between a polysiloxane containing Si—H bonds, an &agr;,&ohgr;-dihydroxypolydiorganoiloxane and an amino-functional dialkoxysilane prior to application to fiber materials, the magnitude and/or durability of the effects obtainable on the fiber materials are not optimal. This applies in particular when nonwovens are treated with polysiloxane compositions. The use of prior art compositions here frequently leads to nonoptimal nonwoven properties as regards obtainable effects and processibility of nonwovens.
Disadvantages also result on using polysiloxane compositions prepared using high molecular weight polysiloxanes or polysiloxanes which contain relatively large amounts of R SiO
1.5
units and which are high molecular weight, i.e. which contain Si atoms to which three oxygen atoms are attached.
It is an object of the present invention to provide improved polyorganosiloxane mixtures for treating fiber materials, preferably textile fabrics, especially nonwovens. The improved polyorganosiloxane mixtures shall be stable in storage, both neat and in the form of aqueous dispersions having a suitable pH, and impart hydrophobic properties to fiber materials treated therewith, and the adhesion of the polysiloxane mixtures to the fiber material shall be good even after laundering operations.
This object is achieved by a polyorganosiloxane mixture obtainable by reacting a linear polyorganosiloxane A) containing 5 to 70, preferably 10 to 60, silicon atoms, units of the general formula (I)
and optionally units of the general formula (II)
and having end groups formed by (R
1
)
3
Si—O— radicals or by H(R
1
)
2
Si—O— radicals, with a linear &agr;,&ohgr;-dihydroxypolydiorganosiloxane B) containing 10 to 150, preferably 20 to 80, silicon atoms, units of the abovementioned general formula (II) and optionally in addition units of the formula (IV)
and having end groups formed by HO Si(R
1
)
2
—O— radicals and with a silane C) of the general formula (III)
and optionally with a linear polyorganosiloxane D) containing either units of the formula (I) or of the modified formula (I) where the hydrogen atom is replaced by OH and additionally units of the formula (IX)
and optionally units of the formula (II), the end groups of the polyorganosiloxane D) being formed by (R
1
)
3
Si—O— radicals or by HO(R
1
)
2
Si—O— radicals,
wherein every R
1
is independently an alkyl radical of 1-6 carbon atoms or a phenyl radical, preferably a methyl radical, every R
2
is independently an alkyl radical of 1-6 carbon atoms, preferably a methyl or ethyl radical, Y is a radical of the formula V, VI, VII or VIII
 —CH
2
—CH(R′″)—&Parenopenst;CH
2
&Parenclosest;
k
—NH&Brketopenst;&Parenopenst;CH
2
&Parenclosest;
t
—NH&Brketclosest;
l
R
5
  (V)
where
R′″ is H or CH
3
,
one of R′ and R″ is hydrogen and the other is CH
3
,
m is from 5 to 40,
k is from 0 to 6, preferably 1,
t is from 2 to 8, preferably from 2 to 4,
n is from 0 to 10,
l is from 0 to 3, preferably 0 or 1,
R
5
is H, —CO—CH
3
, —CO&Parenopenst;CH
2
&Parenclosest;
k
OH, —CH
2
&Parenopenst;CH
2
&Parenclosest;
k
CH
3
or cyclohexyl and x is from 1 to 3, preferably 1 or 2,
the reaction being carried out without polyorganosiloxane containing units of the general formula R
4
SiO
1.5
where R
4
is a monovalent organic radical, as starting material and the reaction being carried out in such a way that the number of the Si—H units present in the polysiloxane mixture obtained is 60 to 95% of the number of Si—H units which were present in the form of the components A) and D) prior to the reaction and the reaction being carried out without use of a metal-containing crosslinking or condensation catalyst.
The polyorganosiloxane mixtures of the invention are preparable by reacting the three starting materials A, B and C mentioned above and in claim 1 and optionally the starting material D. This reaction can be effected by initially mixing all three or four starting materials in the presence or absence of an organic solvent. When a solvent is used, it has to be inert, i.e. it must not enter chemical reactions with the starting materials, with the intermediates and with the polysiloxanes formed as end products. Preferably, no organic solvent is used.
The three or four starting materials mentioned need not all be present from the start, only two or three thereof. It will be advantageous in many cases if, in the reaction, the addition of one of the components A) and C) to the reaction mixture only takes place after the addition of component B). The procedure in this case is to start the reaction with a mixture of A) and B) and optionally D) or of B) and C) and optionally D) and to add component C) or A) respectively later. The reaction may similarly be carried out by using at the start only a portion of the cont

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