Flooring adhesives based on styrene-butadiene copolymers

Details Flooring adhesives based on styrene-butadiene copolymers Flooring adhesives based on styrene-butadiene copolymers

2001-10-22

2003-07-15

Yoon, Tae H. (Department: 1714)

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...

C524S270000, C524S272000, C524S821000, C524S823000

Reexamination Certificate

active

06593421

ABSTRACT:

The present invention relates to aqueous compositions containing from 1 to 60% by weight of a polymer A) built up from
a) from 10 to 50% by weight of a vinylaromatic having up to 20 carbon atoms,
b) from 45 to 75% by weight of a nonaromatic hydrocarbon having two conjugated double bonds,
c) from 0 to 20% by weight of a water-soluble monomer having a water solubility of at least 100 g per liter of water under standard conditions (21° C. and 1 bar), the water-soluble monomer containing no acid group or acid anhydride group,
d) from 0.1 to 4.5% by weight of a monomer containing at least one acid group or acid anhydride group,
e) from 0 to 30% by weight of a monomer other than a) to d),
and from 40 to 99% by weight of a filler B), the weight data for A) and B) being based on the sum of A) and B).
Aqueous dispersions of styrene-butadiene copolymers and their use as binders in adhesives for floor coverings are known from U.S. Pat. Nos. 5,565,511 and 5,962,564.
EP-A-620243, EP-A-962510 and WO 9937716 describe flooring adhesives and their preparation. The flooring adhesives therein are essentially based on polyacrylate binders, the description also mentioning vinylaromatics and dienes as monomers of which the binder may be composed.
Adhesives generally are required to display good adhesion—in other words, to stick well to the substrate—and good cohesion—in other words, to hold together well within the adhesive film. Adhesives for floor coverings are subject to particular requirements. Here, there is the desire in particular for good wet bonding capacity. A good wet bonding capacity means that after a carpet, for example, has been laid on the substrate which is coated with the aqueous dispersion, the carpet can initially still be aligned and its position corrected but that, soon thereafter, a slipproof bond develops whose strength increases as drying progresses.
A good dry gripping capacity means that even after a long period of ventilation a carpet, after having been laid on the substrate, which is then dry, gives a firm, slipproof bond.
A further desired aim is to dispense with volatile organic constituents, such as solvents or plasticizers, in order to avoid subsequent exposure to corresponding emissions.
Further important requirements are that the binders are readily processable with tackifier resins, e.g., rosins, and that the formulations obtained have a high stability.
Existing flooring adhesives based on styrene-butadiene copolymers do not yet meet the diverse and different requirements in this sector to a satisfactory extent.
It is an object of the present invention to provide flooring adhesives based on styrene-butadiene copolymers which satisfy the requirements described above as far as possible and result in a balanced profile of properties.
We have found that this object is achieved by the composition described above and by its use as a flooring adhesive.
The aqueous composition preferably contains
from 10 to 45% by weight,
with particular preference from
10 to 30% by weight, of the
polymer A) defined at the outset,
and
from 55 to 90% by weight,
with particular preference from
70% by weight to 90% by weight,
of a filler B).
The percentages by weight are based on the total weight of A) and B).
In one preferred embodiment the aqueous composition further comprises a tackifying resin C), also referred to as a tackifier.
The amount of the tackifier is preferably from 1 to 50 parts by weight, with particular preference from 5 to 30 parts by weight, based on the 100 parts by weight of the sum of A)+B).
On the composition of the polymer A):
The weight fraction of the monomer c) in the polymer is preferably from 0.1 to 20% by weight, with particular preference from 5 to 15% by weight, based on the polymer.
Especially if the monomer d) content is not more than 4% by weight, the fraction of the monomer c) is from 0.1 to 20% by weight, preferably from 5 to 15% by weight.
Moreover, the following compositions of the polymer A) are preferred:
a) from 10 to 40% by weight, with particular preference from 20 to 30% by weight.
b) from 50 to 75% by weight, with particular preference from 55 to 65% by weight.
c) from 0.1 to 20% by weight, with particular preference from 1 to 20% by weight.
d) from 0.1 to 4.5% by weight, with particular preference from 0.1 to 4% by weight.
e) from 0 to 30% by weight, with particular preference from 0 to 10% by weight.
The weight data for the monomers of the polymer A) in each case add up to 100% by weight.
Examples of suitable monomers a) include vinyltoluene, &agr;- and p-methylstyrene, &agr;-butylstyrene, and styrene. Styrene is preferred.
Examples of suitable monomers b) include butadiene, isoprene, and chloroprene. Butadiene is preferred.
Preferred monomers c) have a water solubility of at least 300 g per liter of water (21° C., 1 bar), with particular preference at least 700 g/liter of water.
Preferred monomers c) are those containing a nitrile group.
Particular preference is given to acrylonitrile and methacrylonitrile.
Suitable monomers d) are acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and their anhydrides and monoesters.
Particular preference is given to itaconic acid, acrylic acid, and methacrylic acid.
With particular preference, monomers d) comprise itaconic acid or a mixture of monomers containing at least 20% by weight of itaconic acid.
Further monomers e) may be, for example, C
1
-C
20
alkyl (meth)acrylates, vinyl esters having up to 20 carbon atoms, vinyl halides or other monomers, provided that they do not affect the water solubility of the monomers c).
The polymer A) has a low crosslinking density.
For a given monomer composition, a suitable measure of the crosslinking density is the transverse nuclear magnetic resonance relaxation time of the protons chemically bonded to the polymer (
1H
T
2
). In this document, it was determined on a sample of the respective aqueous polymer dispersion, filmed at 25° C. and then dried at 80° C. for 2 h, at a sample temperature of 140° C. and a
1
H resonance frequency of 20 MHz. The relationship between
1H
T
2
and the crosslinking density is described, for example, in Macromolecules 1994, 27, 2111-2119. Ultimately it is based on the fact that the transverse nuclear magnetic resonance relaxation time of an atomic nucleus having a magnetic moment is, on the one hand, a measure of the mobility of said nucleus in an external magnetic field, and crosslinking of polymer chains different from one another restricts their mobility. The lower the mobility of a polymer chain, i.e., the greater the crosslinking density, the shorter the transverse nuclear magnetic resonance relaxation time of atomic nuclei chemically bonded to this polymer chain and having a magnetic moment.
In the case of the polymer A),
1H
T
2
is preferably greater than 10 ms, with particular preference greater than 12 ms (ms=milliseconds).
The glass transition temperature of the polymer is preferably from −60 to −10° C., in particular from −40° C. to −15° C., and with very particular preference from −15 to −30° C.
The glass transition temperature of the polymer may be determined in accordance with customary methods such as differential thermoanalysis or differential scanning calorimetry (see, e.g., ASTM 3418/82, midpoint temperature).
The polymer A) is prepared in general by means of free-radical addition polymerization. Suitable polymerization methods, such as bulk, solution, suspension or emulsion polymerization, are known to the skilled worker.
The copolymer is preferably prepared by solution polymerization with subsequent dispersion in water or, with particular preference, by emulsion polymerization, to give aqueous copolymer dispersions.
The emulsion polymerization may be conducted batchwise, with or without the use of seed lattices, with all or some constituents of the reaction mixture being included in the initial charge, or, preferably, with some being included in the initial charge and the remainder of all or some constituents of the reaction mixture being meter

Affiliated with

Also associated with

Rating

Flooring adhesives based on styrene-butadiene copolymers does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Flooring adhesives based on styrene-butadiene copolymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flooring adhesives based on styrene-butadiene copolymers will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3037128