NO801442L - ASFEST FLOOR FILTER. - Google Patents

Description

•The present invention relates to asbestos-free, rubberized Invention©!©tn concerns mt r sp©§i@lfe ffl§€£§4§fVårloed, asbestos-free/rubberized filters which are dimensionally stable and consequently suitable for use as a felt base for elastic floor coverings.

Asbestos-containing rubberized filters are well known and have achieved unprecedented commercial success in the flooring industry as a "substrate material for decorative floor coverings. These asbestos-containing rubberized filters are produced by saturating asbestos fibers in a Dutcher with a rubber latex in an aqueous system and forming the felt product in conventional paper machines. See e.g., US Patent Nos. 2,375,245, 2,613,190, and 2,759,813. The commercial success of these asbestos-containing rubberized filters is mainly due to the physical and chemical properties imparted to the felts by the asbestos fibers. The asbestos fibers alone facilitate the manufacture of filters that are easy can be treated,

are dimensionally stable, exhibit good heat-tensile strength and are alkali, moisture and microbiological resistant. No other fibrous material is known which can replace asbestos fibers in floor filters and which provides a filter with acceptable properties, especially dimensional stability and heat-tensile strength.

The health risk problems with asbestos fibers are also well-known and the floor covering industry has thus long searched for replacement floor filters that do not contain asbestos fibers, but

which nevertheless provide essentially the same physical and chemical properties as the previously known asbestos-containing rubbers; filter. It is particularly important and critical for the floor covering industry that the replacement floor felt is dimensionally stable and exhibits good heat-tensile strength.

If a floor felt does not show "good heat-tensile strength", it will not withstand the temperatures that are common for treating elastic floor coverings.

If a floor felt is not dimensionally stable, it will swell when exposed to moisture and thereby cause the entire floor covering to grow. This growth represents a major problem when laying. During laying, when the felt comes into contact with wet adhesive or adhesive, it grows and this growth results in distortion of an "in-register" decorative pattern at double-cut seams. This growth can also result in folds or creases in the floor covering.

The present invention helps solve the above-mentioned problems and provides a Dutch-saturated, wet-laid, asbestos-free, rubberized felt which is dimensionally stable.

For the purposes of the invention, a felt that shows more than 0.30% change in the width direction is considered to be unsuitable for use in the production of floor coverings.

The term "dimensional stability" used means that the floor felt exhibits +0.30% or less and preferably +0.20% or less, growth change in the width direction when examined in the standardized dimensional stability test at high humidity as stated below.

Two felt samples of 2.5x22.5 cm for testing are cut

from the felt in the width direction. When testing a felt handsheet made in a handsheet form that has no machine or cross-machine direction (width direction), shearing is not important. Each sample is tested individually as follows: Conditions for dimensional stability test at high . moisture (1) The sample is placed in an oven with circulating air and heated for 6 hours at 82.2°C.

(2) The sample is removed from the oven and cooled in a desiccator above

CaCl2 for 1/2 hour at 23°C.

(3) The sample is removed from the desiccator and the distance between two reference points (start distance) is measured to the nearest 0.025 mm. (4) The sample is then placed in a humidity chamber and heated for 24 hours at 37.8°C and 90% relative humidity. (5) The sample is removed from the humidity chamber and cooled in a desiccator for 1/2 hour over water. (6) The sample is removed from the desiccator and the distance between the two reference points (end distance) is measured again to the nearest 0.0 25 mm, and the initial distance is subtracted from the end distance to obtain the change in mm.

The resulting change in mm is divided by the initial distance in mm and multiplied by 100 to obtain the higher sample's %-wise change. The mean for the %-wise for--" change for each of the two samples is determined so that the %-wise change in width ©tningm, hVålK@| jfflålS" unit £6r dimenéioneetabilit;kit is obtained. federai- Standard 501a, Method 6211.

According to the present invention, it is provided

a "beater"-saturated, water-laid, asbestos-free, rubberized floor mat 'which is dimensionally stable, prepared by removing water from an aqueous starting composition comprising glass fibers,* cellulose pulp, fibrillated polyolefin fibers, at least one inorganic filler, a synthetic rubber binder, a soluble salt selected from the group consisting of aluminum salts, ferric salts and stannous salts, and a sufficient amount of an alkaline hydroxide to achieve a pH value in the range from about 6 to approx. 10, where the alkaline hydroxide serves to convert the soluble salt into a water-insoluble hydroxide.

According to the invention, there is also provided a surface covering comprising (a) a "beater"-saturated, water-laid, asbestos-free, rubberized floor felt which is dimensionally stable, produced by removing water from an aqueous starting composition comprising glass fibres, cellulose pulp, fibrillated polyole fine filters, at least one inorganic filler, a synthetic rubber binder, a soluble salt selected from the group consisting of aluminum salts, ferric salts, stannous salts and a sufficient amount of an alkaline hydroxide to achieve a pH value in the composition in the range from about 6 to approx. 10, wherein the alkaline hydroxide serves to convert the soluble salt to a water-insoluble hydroxide, and (b) a decorative wear surface joined to the rubberized floor felt.

In its preferred form, the aqueous starting composition will also contain a papermaking wet strength resin and a latex antioxidant. The starting seam- . the sentence may possibly contain retention agents, bio-ciders and the like.

The aqueous starting composition will contain from

about. 1 to approx. 10 parts by weight of conventionally surface-treated, chopped glass fibers per 100 parts of the total fiber and filler weight. Suitable glass fibers will have nominal fiber lengths in the range from approx. 1.59 mm to approx. 12.7 mm and nominal

fiber diameters in the range from approx. 0/0051 mm to approx. 0.013 mm.

Two types of particularly suitable chopped glass fibers are commercially available as 3.18 mm "D-E 636 Glass Fibers" and 3.18 mm "D-E 670-8 Glass Fibers".

The aqueous starting composition will contain from

about. 2 to approx. 20 parts by weight of cellulose pulp per 100 parts of

• the total fiber and filler weight. In order to determine quantities of constituents, in the present invention cellulose pulp is considered a fiber constituent. Any suitable cellulosic pulp may be used including bleached and unbleached sulphite pulp, softwood pulp, kraft pulp, newsprint pulp and the like. A particularly suitable cellulose pulp is "Unbleached Sulphite Pulp"

(ITT Rayonier) .

Any suitable fibrillated polyolefin fibers can be used in an amount of from approx. 1 to approx. 20 parts by weight of fibri- . leather polyolef inf ibere per 100 parts of the total fiber;' and filler weight. Particularly suitable fibrillated polyolefin fibers are fibrillated polyethylene fibers and fibrillated polypropylene fibers.

A particularly suitable fibrillated polyethylene fiber is quali-

tet E-620 "Fybrel" and this fiber has a weight average fiber length of 1.3 mm measured in a Bauer-McNett classification system and a drainage factor of 6 sec./gram. The drainage factor corresponds to the drainage rate of a 10 g sample measured in a "Standard British" hand sheet form expressed in seconds per gram.

Other fibrillated polyolefin fibers that can be used are grades E-400, E-600/E-780, E-790 and R-830 of the "Fybrel" type, grades A and D of the "Pulplex E" type, both of which are fibrillated polyethylenes, and the quality AD of the type "Pulplex E" a fibrillated polypropylene.

The aqueous starting composition will contain at least

an inorganic filler which is present in an amount in the range from approx. 50 to 96 parts by weight total inorganic filler pir.

100 parts of the total fiber and filler weight. The inorganic filler is selected from the group consisting of paper, filler clay, wollastonite, talc, calcium carbonate, mica, pyrophyllite and diatomaceous earth. Particularly suitable fillers are

wollastoriite of the grade P-4, P-l or C-l, and kaolin clays designated "Hi-Opaque Clay", and "Klondyke" clays or "Klondyke KWW" clays. Pyrophyllite is a hydrous aluminum silicate with the commercial name "Pyrax".

The aqueous starting composition contains from approx.

10 to approx. 40 parts by weight of a synthetic rubber latex per 100 . • parts of the total fiber and filler weight. Any suitable synthetic rubber latex may be used including styrene/butadiene latexes, carboxylated styrene/butadiene latexes, polychloroprenes, carboxylated polychloroprenes, vinylpyridine/styrene/butadiene terpolymers and the like. Carboxylated styrene/butadiene latexes are particularly suitable for use in the present invention and such a material is designated "Dylex 1187". "Dylex 1187" has a total solids content of approx. 44-50% by weight, a pH value of 9-10, a surface tension of 60-70 dyne/cm, a Brookfield viscosity of 1-300 and a weight of 10.1 kg/litre.

The aqueous starting composition preferably contains from approx. 0.02 to approx. 2 parts by weight ("add-on") of a conventional resin of papermaking wet strength per 100 parts of the total fiber and filler weight. Particularly suitable wet strength resins are designated "Kymene 2064" and "Kymene 557H".

These materials are aqueous solutions of cationic amine polymer-epichlorohydrin adducts.

The aqueous starting composition preferably contains from approx. 0.2 to approx. 1.6 parts by weight ("add-on") of a latex antioxidant per 100 parts of the total fiber and filler weight. A particularly suitable antioxidant is designated "Flectol H" and is polymerized 2,2,4-trimethyl-1,2-dihydroquinoline. •

The following examples illustrate the production of dimensionally stable, asbestos-free, rubberized floor filters according to the invention. Example I

This mixing method is based on the preparation of an aqueous composition using the following ingredients. All stated quantities are parts per 100 parts by weight. of the total fiber and filler weight.

To a mixing container containing approx. In 300 ml of water, tap water, the total quantities of glass fibre, fibrillated polyethylene, cellulose pulp, filler and antioxidant were added. The contents of the mixing container were slurried for approx. 1/2-1 minute to ensure complete dispersion of the ingredients.

The slurry was then diluted with tap water at a temperature of approx. 24°C to a total volume of

2.3 liters at 2% consistency and was then mixed using an air tube device.

To the resulting homogeneous mixture, the total amount of wet strength resin was added with stirring for approx. 1 minute.

The total amount of aluminum sulfate was then add-

set under stirring for approx. 2 minutes followed by the addition of ammonium hydroxide until the slurry had a pH value of approx. 7-7.5. •"

The total amount of synthetic rubber latex was then added with stirring for approx. 5 minutes until the latex-precipitated, i.e. the latex settled on the fibers and the filler and thus serves as a drainage aid and a binder"

in the resulting felt.

The resulting bpp slurry was then formed into a handsheet using a conventional Williams handsheet mold. The resulting hand sheet was then wet-pressed to remove excess moisture and tumble dried at a temperature of approx. 110°C.

The resulting dried hand sheet was obtained as rubberized floor felt according to the invention suitable for use in the production of elastic floor coverings. The felt was tested and found to have a thickness - after calendering - of approx. 0.635 mm..

Example II

This mixing method is based on the preparation of an aqueous composition using the following ingredients. All amounts of ingredients are in parts per 100 Weight parts of the total fiber and filler weight.

To a mixing container containing approx. 300 mm water-tap water, the total amount of glass fiber, fibrillated polyethylene, cellulose pulp, filler and antioxidant was added. The contents of the mixing container were slurried for approx. .1/2-1 minute to ensure complete dispersion of the constituent parts.

The slurry was then diluted with tap water at a temperature of approx. 24°C to a total volume of

2.5 liters at .2% consistency and homogeneously mixed using an air stirrer.,

To the resulting homogeneous mixture, the double amount of wet strength resin was added with stirring for approx. 1 minute.<*>

The total quantity of aluminum sulphate was then added while stirring for approx. 2 minutes followed by the addition of ammonium hydroxide to a slurry pH of 7-7.5.

The total amount of synthetic rubber latex was then added with stirring for approx. 5 minutes until the latex precipitated, i.e. the latex was deposited on the fibers and filler and thus serves as a drainage aid and a binder in the resulting felt.

The resulting slurry was then formed into a handsheet using a conventional Williams handsheet mold. The resulting hand sheet was then wet-pressed to remove excess moisture and tumble dried at a temperature of approx. 110°C.

The resulting dried hand sheet was obtained as

a rubberized floor felt according to the invention suitable for use in the production of elastic floor covering. The felt was tested and found to have a thickness of approx. 0.625 mm.

Example III

Using substantially the same method as in Example II, a hand sheet was produced using the following ingredients.

The resulting hand sheet was obtained as a rubberized floor felt according to the invention suitable for use in the production of elastic floor covering. The felt was tested and found to have a thickness of approx. 0.61 mm. ;

Example IV

Using essentially the same method as in Example II, a hand sheet was produced using the following ingredients.

The resulting hand sheet was obtained as a rubberized floor felt according to the invention suitable for use in the production of elastic floor coverings. The felt was tested and found to have a thickness of approx. 0.635 mm. Example V Using essentially the same method as in Example II, a hand sheet was produced using the following ingredients. 'in

The resulting hand sheet was obtained as a rubberized floor felt according to the invention suitable for use in the production of elastic floor coverings. The felt was tested and found to have a thickness of approx. 0.635 mm. •

Example VI

Using essentially the same method as in Example II, a hand sheet was produced using the following ingredients. This slurry was diluted to a total volume of 2.5. liter at 1.25% consistency instead of 2% consistency.

The resulting hand sheet was obtained as a rubberized floor felt according to the invention suitable for use in the production of elastic floor coverings. The felt was tested and found to have a thickness of approx. 0.634 mm.

Example VII

Using substantially the same method as in Example II, a hand sheet was prepared using the following ingredients.

The resulting hand sheet was obtained as a rubberized floor felt according to the invention, suitable for use in the production of elastic floor coverings. The felt was tested and found to have a thickness of approx. 0.770 mm. Example VIII

Using substantially the same method as i1, example II, a hand sheet was prepared using the following ingredients. This slurry was diluted to a total volume of 2.5 liters at 1.33% consistency instead of 2% consistency.

The resulting hand sheet was obtained as a rubberized floor felt according to the invention suitable for use in the production •' of elastic floor coverings. The felt was tested and found to have a thickness of approx. 0.599 mm.

Example IX

This example demonstrates the best method for producing asbestos-free rubberized floor felt according to the invention.

Into a hydra mass solver containing water they became

total amounts of cellulose pulp, fibrillated polyethylene fibres, filler and antioxidant, added. The contents of the pulp solvent were slurried for approx. 10-15 minutes to ensure complete dispersion of the ingredients.

The slurry was passed successively through Jordan refiners, a holding tank, and to a settling tank where it was diluted with water at 3% consistency and where total amounts of glass fibers, synthetic rubber latex, wet strength resin, aluminum sulfate, and ammonium hydroxide were added at about -stirring for about 3-5 minutes.The batch weight for 100 parts of fiber

and filler in settling tanks was 1125 kg.

The total amount of retention aid was allowed into the composition as it was pumped from the settling tank to a conventional Fourdrinier machine where it was formed into a felt according to the invention. The felt got wet-

pressed to remove excess moisture and drum dried

at a temperature of from approx. 135 to approx. 149°C.

The resulting felt was obtained as a rubberized floor felt according to the invention and used for the production of elastic floor coverings. The felt was tested and found to have a thickness, after calendering, of approx. 0.610 mm.

The following Table I illustrates physical and chemical data for asbestos-free filters from Examples I-IX compared

with representative average data for conventional previously known asbestos-containing rubber filters: 1

The above data indicate that the asbestos-free rubberized filters according to the invention exhibit excellent dimensional stability under conditions of high humidity while maintaining acceptable physical and chemical properties compared to the previously known asbestos-containing rubberized filters.

The asbestos-free rubberized filters with the composition according to the invention can, using conventional *.,/".■ methods are laminated together with a conventional decorative surface coating such as a vinyl wear layer to produce floor coverings.

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Claims (12)

1. Asbestos-free, floor felt, characterized in that it is in parts by weight per 100 parts of the total fiber and filler weight comprises from approx. 1 to approx. 10 parts fiberglass; from approx. 2 to approx. 20 parts cellulose pulp; from approx. 1' to approx. 20 parts fibrillated synthetic fibers; from approx. 50. to about; 96 total number of parts of at least one inorganic filler; and from approx. 10 to approx. 40 parts "add-on" of a binder. 2. Floor felt according to claim 1, characterized in that it in parts by weight per 100 parts of the total fiber and filler weight comprises from approx. 1 to approx. 5 parts fiberglass; from approx. 4 to approx. 15 parts cellulose pulp; from approx. 1 to approx. 10 parts fibrillated synthetic fibers; from approx. 70 to cal 90 total parts of at least one inorganic filler; and from approx. 10 to approx. 25 parts "add-on" of a binder. 3. Floor felt according to claim 1 or 2, characterized in that the fibrillated fibers are fibrillated polyolefin fibers. 4. Floor felt according to claim 1 or 2, characterized in that the binder is a synthetic rubber binder. 5. Floor felt according to claim 1 or 2, characterized in that the inorganic filler is selected from the group consisting of paper filler clay, wollastonite, talc: calcium carbonate, mica, pyrophyllite and diatomaceous earth. 6. Floor felt according to any one of claims 1-5, characterized in that it comprises a papermaking wet strength resin. 7. Floor felt according to claim 6, characterized in that it comprises from approx. 0.02 to approx. 2 parts "add-on" of said resin... 8. Floor felt according to any one of claims 1-7, characterized in that it comprises a latex antioxidant. 9. Floor felt according to claim 8, characterized by the fact that it includes from approx. 0.2 to approx. 1.6 parts "add-on" of said antioxidant. 10. A floor felt according to any one of claims 1-9, characterized in that it has dimensional stability of +0.30% or less when measured under the conditions of the dimensional stability test at high humidity. 11. Floor felt according to claim 10, characterized in that it has a dimensional stability of +0.20% or -less at the aforementioned stability test. 12.. Floor felt according to claims 1-11, characterized in that it comprises a decorative wear surface joined with said floor felt to produce a surface coating. in % • I