Method for laying parquet flooring with improved dimensional stability

Abstract

1) Moisture-crosslinkable adhesive composition comprising: from 25% to 50% of a composition (a) formed of a crosslinkable epoxy resin and of a polymer having a polyoxyalkylene or polyurethane main chain connected to a hydrolyzable terminal alkoxysilyl group; from 0.5% to 6% of a ketimine (b); and from 40% to 65% of an inert inorganic or organic filler (c). 2) Method for laying a wood-based covering, in particular a wide-block parquet flooring, on a flat rigid support comprising the distribution of an effective amount of said adhesive composition in the form of a substantially homogeneous layer.

Claims

1. A moisture-crosslinkable adhesive composition comprising: from 25% to 50% of a composition (a): of 5% to 37% weight/weight of a crosslinkable epoxy resin (a1) of bisphenol A type, and of 63% to 95% weight/weight of a polymer (a2) comprising a main chain of (i) a polyoxyalkylene or (ii) a polyurethane, which is connected to two hydrolyzable terminal alkoxysilyl groups, said groups being bonded, in the case of a main chain (i), to a methylene radical which is itself bonded to the ends of the chain (i) by a divalent group A having one of the following formulae:
OCONH(Ia);
NR.sup.1CONH(Ib), in which R.sup.1 represents a hydrogen atom or a C.sub.1-C.sub.3 alkyl radical; and
SCONH(Ic); from 0.5% to 6% of a ketimine (b) as precursor of a crosslinking agent for the epoxy resin (a1); and from 40% to 65% of an inert inorganic or organic filler (c); the contents of ingredients (a), (b) and (c) being expressed as weight/weight percentages with respect to the total weight of said adhesive composition, wherein the hydrolysable terminal alkoxysilyl groups have the formula:
Si(R.sup.2).sub.p(OR.sup.3).sub.3p(II) in which: each R.sup.2 and R.sup.3 independently represents a linear or branched alkyl radical of 1 to 4 carbon atoms; and P=1.

2. The adhesive composition as claimed in claim 1, wherein crosslinkable epoxy resin (a1), is bisphenol A diglycidyl ether of formula: ##STR00007##

3. The adhesive composition as claimed in claim 1, wherein the polymer (a2) has a polypropylene glycol main chain (i) and the divalent group A is of formula (Ia).

4. The adhesive composition as claimed in claim 1, wherein the polymer (a2) has a polyurethane (ii) for main chain.

5. The adhesive composition as claimed in claim 1, wherein the content of crosslinkable epoxy resin (a1) included in the composition (a) is 10% to 33% and the content of polymer (a2) in this same composition is 67% to 90%.

6. The adhesive composition as claimed in claim 1, wherein the ketimine (b) has the formula:
(R.sup.6R.sup.7CN).sub.qR.sup.5(IV) in which: R.sup.5 is an organic radical having from 1 to 3 free valences; R.sup.6 and R.sup.7, which are identical or different, represent a hydrogen atom, a phenyl group or an alkyl group having 1 to 6 carbon atoms, which is optionally substituted; q is an integer equal to 1, 2 or 3.

7. The adhesive composition as claimed in claim 6, wherein the ketimine (b) has formula (IV) in which q is equal to 2, R.sup.5 is a divalent radical derived from isophorone, R.sup.6 is methyl and R.sup.7 is isobutyl.

8. The adhesive composition as claimed in claim 6, wherein R.sup.5 is optionally substituted C.sub.1-12-alkyl or C.sub.6-24-aryl.

9. The adhesive composition as claimed in claim 1, wherein the inorganic filler (c) is calcium carbonate or a fumed silica.

10. The adhesive composition as claimed in claim 1, comprising: a content of the composition (a) of 30% to 40%; a content of ketimine (b) of 1% to 5%; and a content of the inorganic filler (c) of 50% to 60%.

11. The adhesive composition as claimed in claim 1, wherein the polymer (a2) has a polyoxyalkylene (i) for main chain and divalent group A is of formula (Ia).

12. The adhesive composition as claimed in claim 1, wherein polymer (a2) has the formula (R.sup.3O).sub.2(R.sup.2)SiCH.sub.2NHC(O)O-polyoxyalkylene-C(O)NHCH.sub.2Si(R.sup.2)(OR.sup.3).sub.2 wherein each R.sup.2 and R.sup.3 independently represents a linear or branched alkyl radical comprising 1 to 4 carbon atoms; and wherein the polyoxyalkylene corresponds to a repeat unit of R.sup.4O, in which R.sup.4 represents a linear or branched alkylene comprising from 1 to 5 carbon atoms.

13. A method for laying a wood-based covering on a flat rigid support, comprising distributing, over the surface of said support, an effective amount of the adhesive composition as defined in claim 1.

14. The laying method as claimed in claim 13, wherein the wood-based covering is a parquet flooring.

15. The laying method as claimed in claim 13, wherein the adhesive composition is distributed over the support in the form of a substantially homogeneous layer.

16. An assemblage comprising a flat rigid support covered with a wood-based covering via a substantially homogeneous layer of the adhesive composition, as defined in claim 1, which is crosslinked and forms an adhesive joint.

17. The assemblage as claimed in claim 16, wherein the covering is a parquet flooring that can be used as a floor.

Description

EXAMPLES 1 TO 5

(1) Moisture-crosslinkable adhesive compositions are prepared by simple mixing at ambient temperature of the ingredients shown in the following table, after drying the inert filler (c). In addition to these ingredients, the composition also comprises 1.5% of dehydrating and adhesion-promoting agents, 1% of reactive diluent, 0.5% of a fumed silica and 5% of Hydroseal G3H.

(2) The adhesive compositions obtained are subjected to the following measurements and test.

(3) Measurement of the Young's Modulus and of the Tensile Elongation at Break of the Crosslinked Composition:

(4) This measurement is carried out in accordance with standard NF ISO 37.

(5) A dumbbell test specimen of Type 1 (length of the narrow part of the dumbbell equal to 25 mm for a width of 6 mm and a thickness of 2 mm) is obtained by cutting out with a hollow punch from a film of the adhesive composition crosslinked beforehand after residing for 7 days in an atmosphere maintained at 23 C. and 50% relative humidity.

(6) The test specimen thus obtained is drawn in a tensile testing machine, the movable jaw of which moves at a constant rate equal to 50 mm/minute. The stress applied and the elongation of the test specimen (expressed as %) during the drawing thereof and at the time of the failure thereof are recorded.

(7) The Young's modulus (expressed in MPa) is the slope of the tangent to the origin of the curve plotting the tensile stress as a function of the elongation.

(8) The results are shown in the table.

(9) Measurement of the Elongation at Break by Shearing of the Crosslinked Composition:

(10) An assemblage of 2 parquet blocks adhesively bonded by means of the adhesive composition is prepared in accordance with standard NF EN 14293.

(11) Two rectangular oak blocks with a length of 14 cm, a width of 2.4 cm and a thickness of 1 cm are used.

(12) The adhesive composition is applied so as to obtain adhesive bonding by overlapping the 2 blocks over a surface area of approximately 600 mm.sup.2, the thickness of the adhesive layer being 1 mm.

(13) The crosslinking of the composition resulting in the formation of the adhesive joint is obtained by maintaining the assemblage at 23 C. and 50% relative humidity for 7 days.

(14) The assemblage thus obtained is inserted into the jaws of a tensile testing machine and a tensile force is applied at a constant rate equal to 20 mm/minute, resulting in the shearing of the adhesive joint, until the latter fails.

(15) The value of the elongation is determined (as %) and recorded in the table.

(16) Test of the Adhesion of Parquet Flooring Adhesively Bonded to a Concrete Slab:

(17) The adhesion obtained for a parquet flooring adhesively bonded to a concrete slab by employing the adhesive composition is evaluated according to standard NF EN 14293.

(18) Use is made of a square concrete slab with a side length of 50 cm and a thickness of 5 cm.

(19) The adhesive composition is uniformly distributed over the surface of this slab using a serrated spreader, so as to deposit, on said surface, an adhesive layer corresponding to a total amount (or dose) of 1 kg/m.sup.2, corresponding to a thickness of 0.6 mm.

(20) Pieces of parquet flooring made of rough bulk oak, with dimensions of 50 mm50 mm10 mm, are applied in the fresh adhesive layer, in a proportion of 10 pieces per slab, separated by approximately 50 mm.

(21) The slab thus coated is subsequently stored at ambient temperature for 7 days.

(22) The strength of resistance to the separation (or tearing off) between a piece of parquet flooring and the support made of concrete, under the effect of a tensile force exerted in a direction perpendicular to the plane of the slab, is then measured.

(23) The tensile force is generated by means of a dynamometer and is transmitted to the piece of parquet flooring via a metal rod, the base of which substantially covers the piece and which is profiled in a T shape.

(24) This metal rod is rendered integral with the piece of parquet flooring by adhesively bonding its base using an epoxy adhesive, the adhesive joint obtained having a cohesion very much greater than that of the bond between the piece and the concrete surface. The vertical portion of the metal rod (corresponding to the vertical bar of the T) is rendered integral with the shaft of the dynamometer by a pin.

(25) A tensile test is then carried out and the value of the resistance to tearing off, expressed in MPa, is recorded, which value is shown in the table.

EXAMPLE 6 (COMPARATIVE)

(26) Example 1 is repeated, the Spur+* Y 15987 being replaced with MS-S 303H. MS-S 303H is a polymer available from Kaneka, having the structure:

(27) ##STR00006##

(28) The results obtained are shown in the table.

EXAMPLE 7 (COMPARATIVE)

(29) Example 3 is repeated, the Geniosil STP-E 10 being replaced with MS-S 303H. The results shown in the table are obtained.

EXAMPLE 8 (COMPARATIVE)

(30) Example 1 is repeated using the contents shown in the table for the components of the composition (a) and for the other ingredients of the adhesive composition. The results shown are obtained.

(31) TABLE-US-00001 TABLE Example 6 7 8 Components 1 2 3 4 5 (comp.) (comp.) (comp.) Content of D.E.R. 10 25 33 33 33 10 33 40 components 331 (a1) of the Geniosil 67 composition STP-E 10 (a) (in %) (a2)(i) Desmoseal 67 S XP 2636 (a2)(ii) Spur+* Y 67 15986 (a2)(ii) Spur+* Y 90 75 60 15987 (a2)(ii) MS-S 303H 90 67 Content of Composition (a) 31.5 31.5 31.5 31.5 31.5 31.5 31.5 31.5 components Desmophen 1.2 3 4 4 4 1.2 4 4.8 of the LS 2965 A (b) composition Calcium 58.73 57.03 56.40 56.40 56.40 58.73 56.40 55.32 (in %) carbonate (c) TIB KAT 0.57 0.47 0.10 0.10 0.10 0.57 0.10 0.38 226 Young's modulus (in MPa) 12 19 15 11 16 3 9 46 Tensile elongation at break (in %) 36 44 86 118 56 198 115 24 Shear elongation at break (in %) 200 210 294 341 214 361 277 168 Adhesion (in MPa) 3.1 2.8 ND ND 2.5 2.1 3.1 3.3 ND = Not Determined