EP2576140A1

EP2576140A1 - Adhesive composition containing a water-soluble or water-dispersible unsaturated polyester and an ethylene-unsaturated monomer, and uses thereof

Info

Publication number: EP2576140A1
Application number: EP11726913.4A
Authority: EP
Inventors: Lidia Jasinska; Cornelis Eme Koning; Alix Arnaud; Clément HOUGA
Original assignee: Saint Gobain Recherche SA
Current assignee: Saint Gobain Recherche SA
Priority date: 2010-05-28
Filing date: 2011-05-27
Publication date: 2013-04-10
Also published as: WO2011148111A1; FR2960546A1; FR2960546B1

Abstract

The present invention relates to an adhesive composition which contains at least one water-soluble or water-dispersible unsaturated polyester and at least one ethylene-unsaturated monomer. Specifically, said unsaturated polyester is obtained by co-polymerisation of (A) at least one monomeric or oligomeric polyol, (B) at least one unsaturated polycarboxylic acid or one unsaturated acid anhydride and (C) at least one water-soluble polymer containing at least two hydroxyl, amine and/or epoxy reactive functions. The invention also relates to the use of said composition for bonding elements of natural or synthetic materials, in particular abrasive particles, glass or rock fibre and spun glass.

Description

ADHESIVE COMPOSITION COMPRISING AN UNSATURATED WATER-DISSOLVABLE WATER DISPERSIBLE POLYESTER AND A MONOMER

ETHYLENICALLY UNSATURATED AND USES

The invention relates to the field of binders intended to bind together elements made of natural or synthetic material, in particular minerals, such as abrasive particles, glass or rock fibers, and glass threads.

The invention more particularly relates to an adhesive composition which contains at least one unsaturated polyester water-soluble or dispersible in water and at least one ethylenically unsaturated monomer.

It is known to use, for the manufacture of mineral products incorporating particles, fibers or mineral threads, thermosetting resins based on formaldehyde, in particular urea-formaldehyde, melamine-formaldehyde and phenol-formaldehyde resins. These resins have good crosslinking ability, are water soluble, have good affinity for minerals and are relatively inexpensive.

There remains, however, in these resins a variable proportion of free formaldehyde which may persist in the final product. However, it is known that formaldehyde can be detrimental for operators on industrial lines, end consumers and the environment.

The formaldehyde emission regulations are becoming more and more restrictive, forcing mineral product manufacturers to seek alternative solutions to the abovementioned resins.

The object of the present invention is to provide an adhesive composition containing no formaldehyde, capable of bonding together elements consisting of natural or synthetic materials, in particular mineral materials, in particular abrasive particles, glass or rock fibers and yarns. of glass.

The adhesive composition according to the present invention is an aqueous composition which contains at least one water-soluble or water-dispersible unsaturated polyester and at least one ethylenically unsaturated monomer, said unsaturated polyester being obtained by co-polymerization (A) of at least one monomeric or oligomeric polyol, (B) at least one unsaturated polycarboxylic acid or an unsaturated acid anhydride and (C) at least one polymer water-soluble composition containing at least two hydroxyl, amine and / or epoxy reactive functional groups.

By "aqueous composition" is meant a composition which contains at least 20% by weight of water, preferably at most 70% and more preferably 40 to 60%.

In order to improve the dispersion of the unsaturated polyester and / or the ethylenically unsaturated monomer, part of the water may be substituted with an organic solvent, for example tetrahydrofuran (THF) or methyl tetrahydro rofuran. born .

The proportion of water replaced by the solvent is at most equal to 50% by weight, preferably at most 30% and advantageously at most 20%.

The polyol (A) according to the present invention comprises at least two hydroxyl functional groups capable of reacting with the carboxylic functions carried by the abovementioned unsaturated polycarboxylic acid or obtained by the hydrolysis of the unsaturated acid anhydride. Preferably, the polyol comprises at most 35 hydroxyl functions, and advantageously at most 15.

The polyol is a monomeric or oligomeric polyol, that is to say comprising at most 10 monomer residues polyols, preferably at most 4.

Preferably, the polyol (A) is chosen from polyols originating from a renewable source, in particular obtained from plants, such as saccharides, or generated by fermentation of plant materials, such as 1,3-propanediol and 1,4-butanediol.

As an example of saccharides, mention may be made of monosaccharides, preferably containing 3 to 8 carbon atoms, in particular hexoses such as glucose, mannose, galactose, derivatives of these hexoses in the form of alcohols. alicyclics and derivatives of these alicyclic alcohols, such as isosorbide, and oligosaccharides such as maltose, cellobiose, lactose, sucrose, trehalose, raffinose, stachyose and dextrins. The preferred saccharide is isosorbide. The unsaturated polycarboxylic acid (B) comprises at least two carboxylic functions, preferably at most four, and advantageously at most three carboxylic functions, and at least one ethylenic unsaturation.

By way of examples of unsaturated polycarboxylic acid (B), mention may be made of linear or branched aliphatic acids, such as fumaric acid, itaconic acid, maleic acid, traumatic acid, and acid. metaconic acid, citraconic acid and aconitic acid, cyclic acids such as 2,5-furan dicarboxylic acid (dehydromucic acid) and aromatic acids such as phthalic acid, tetrahydrophthalic acid, isophthalic acid, terephthalic acid, trimesic acid or pyromellitic acid.

The unsaturated polycarboxylic acid (B) can also be obtained from the corresponding unsaturated acid anhydride which, by hydrolysis, generates the carboxylic functions. The unsaturated acid anhydride is, for example, maleic anhydride.

Preferably, the unsaturated polycarboxylic acid (B) and the unsaturated acid anhydride are monomeric.

The polymer (C) is water-soluble and thus makes it possible to introduce hydrophilic segments in the co-polyester, which gives it a better solubility in polar solvents such as water.

As indicated above, the polymer (C) contains at least two hydroxyl, amine and / or epoxy functional groups.

The polymer (C) is chosen from the group consisting of poly (oxyalkylenes), for example polyethylene glycols and polyethylenepropylene glycols which may carry one or more additional amino functions, polyvinylpyrrolidones, polyethyleneimines and polyoxazolines. The polymer (C) comprises at least 4 monomer units.

When the polymer (C) is a polyol, it is necessarily different from the polyol (A).

Preferably, the polyethylene glycol has a molar mass of less than or equal to 600 g / mol and advantageously greater than or equal to 200 g / mol.

The ratio of the number of hydroxyl, amine and epoxy functional equivalents to the number of carboxylic functional equivalents ranges from 1.01 / 1 to 2/1, preferably from 1.05 / 1 to 1.5 / 1 and better still 1, 10/1 to 1, 2/1. Preferably, the percentage of the number of monomer units of the polymer (C) to the total number of monomer units of the polyol (A) and the polymer (C) ranges from 70 to 95% and preferably 70 to 85%.

The co-polymerization reaction of the monomeric or oligomeric polyol (A), the unsaturated polycarboxylic acid or the unsaturated acid anhydride (B) and the water-soluble polymer (C) is preferably carried out in the presence of a catalyst. for example titanium n-butoxide (IV). Said agent is generally added in an amount representing 0.005 to 4 mol% of the compound (B) and preferably 0.01 to 1%.

Optionally, an antioxidant may be introduced into the polymerization medium, for example 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, an amount at most equal to 1% of the total weight of the unsaturated polycarboxylic acid and the unsaturated acid anhydride (B).

The co-polymerization is generally carried out at a temperature ranging from 140 to 230 ° C, preferably 150 to 220 ° C, and preferably 160 to 210 ° C. By way of example, the co-polymerization can be carried out in several steps, in particular according to the following thermal cycle: 160 ° C. for 1 to 15 hours, 210 ° C. for 2 to 10 hours at atmospheric pressure and 210 ° C. for 1 to 5 hours under a reduced pressure, of the order of 3 to 5 mbar. The preferred heat cycle is 160 ° C for 1 to 10 hours, 210 ° C for 2 to 2 hours at atmospheric pressure and 210 ° C for 1 to 4 hours under reduced pressure.

The unsaturated co-polyester according to the invention is solid at ambient temperature (of the order of 20 ° C.) and can be easily solubilized or dispersed in water. The co-polyester is also soluble in organic solvents, especially in chlororforme.

The preferred unsaturated co-polyester is a polymer obtained by co-polymerization of isosorbide, maleic anhydride and polyethylene glycol.

As already mentioned, the adhesive composition according to the invention comprises at least one ethylenically unsaturated monomer used as crosslinking agent of the co-polyester.

The ethylenically unsaturated monomer used as the co-polyester crosslinking agent is generally selected from the group consisting of by (meth) acrylic acids and (meth) acrylates, in particular 2-hydroxyethyl methacrylate, methacrylamide, N-vinylpyrrolidone and unsaturated carboxylic acids, especially the unsaturated polycarboxylic acids mentioned above, in particular itaconic acid and citraconic acid, or their anhydrides, in particular maleic anhydride.

The ethylenically unsaturated monomer is preferably soluble in water.

The ethylenically unsaturated monomer is added to the aqueous adhesive composition in such proportions that the weight ratio of unsaturated monomer to co-polyester ranges from 1/10 to 1/1, preferably 1/3 to 1/1.

A free radical initiator may be introduced into the aqueous adhesive composition to initiate crosslinking. By way of example, mention may be made of peroxides, especially 2-butanone peroxide, persulfates and azobisisobutyronitrile (AIBN). The amount of said initiator generally represents 0.5 to 2% of the total weight of the unsaturated co-polyester and the ethylenically unsaturated monomer.

The crosslinking of the aqueous adhesive composition is carried out at a temperature ranging from 50 to 180 ° C, preferably 60 to 150 ° C, for a period which may vary from 5 minutes to 6 hours, preferably 15 minutes to 2 hours.

The crosslinked co-polyester is an amorphous polymer which, therefore, does not have a melting point.

The cross-linked co-polyester has sufficient thermal stability for the intended applications.

The aqueous adhesive composition according to the present invention can be used to bind any type of elements composed of natural or synthetic material, in particular mineral elements such as abrasive particles, glass or rock fibers and glass fibers, especially with a view to making sails and fabrics.

The aqueous adhesive composition according to the invention is particularly intended to be used for producing coated abrasive articles, in particular abrasives whose medium consists of paper or fabrics made from cotton, polyester or a blend of cotton and polyester. These abrasive articles constitute another object of the invention.

The following examples illustrate the invention without limiting it.

In these examples:

the molar mass (in g / mol) is determined by gel permeation chromatography using a modified silica column (PFG® marketed by PSS), 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as eluent and standards of polymethylmethacrylates of a given molar mass;

the polydispersity index is the ratio of the molar mass in mass (M _m ) to the molar mass in number (M _n );

- the number of iodine (in gl _2/100 g of co-polyester) is measured by titration in N-methyl-pyrrolidone. It is representative of the level of unsaturation in the co-polyester;

the thermal stability of the crosslinked product is evaluated by measuring the temperature corresponding to a mass loss of 10%;

the soluble fraction of the crosslinked product (in%) in chloroform and water is measured by weighing;

- The glass transition temperature (Tg) is measured by DSC ("Differential Scanning Calorimetry) at a rate of 10 ° C / min under nitrogen.

EXAMPLE 1

a) Synthesis of Isosorbide Co-Polyester-Maleic Anhydride-Polyethylene Glycol

In a flask equipped with a Vigreux column and a Dean-Stark condenser, 5.85 g (0.04 mole) of isosorbide, 4.13 g (0.042 mole) of maleic anhydride, 5.05 g are added. g (0.0084 mol) of polyethylene glycol (Mn = 600 g / mol) and 0.04 g (5.16 × 10 ^-5 mol) of 1,3,5-trimethyl -2,4,6-tris ( 3,5-di-tert-butyl-4-hydroxy-benzyl) benzene.

The flask is heated to 160 ° C until a uniform reaction mixture is obtained. 3.3 mg of titanium n-butoxide (IV) are then added to 1.5 g of toluene. The reaction mixture is placed under an argon atmosphere and heated at 210 ° C. for 3 hours. The reaction is continued for a further 3 hours at 210 ° C. under reduced pressure (3-5 mbar).

After cooling to room temperature, the reaction mixture is dissolved in chloroform and precipitated in methanol at about 10 ° C. The mixture is then filtered, washed several times and dried under vacuum at 85-90 ° C.

The co-polyester has a molar mass in number (Mn) equal to 4400 g / mol, a polydispersity index equal to 4.5, an iodine number equal to 50 g / 100 g and a glass transition temperature Tg equal to -17 ° C.

The yield of the reaction is 87%.

b) cross-linking of the co-polyester

3 g of the co-polyester obtained in step a) and 5 g of 2-hydroxyethyl methacrylate (HEMA), (Mam).

The weight ratio of the co-polyester to the ethylenically unsaturated monomer is 2/1.

The mixture is heated to 50 ° C and 0.2 g of 2-butanone peroxide is added. After complete homogenization of the mixture, the heating is stopped.

The mixture is deposited on a flat substrate (glass or aluminum) and crosslinked for 15 minutes at 85 ° C. and then 12 hours at 115 ° C.

The characteristics of the crosslinked product are given in Table 1.

EXAMPLE 2

The procedure described in Example 1 is followed in the presence of the following compounds: 3.37 g (0.023 mol) of isosorbide, 4.13 g (0.042 mol) of maleic anhydride, 5.04 g (0.025 mol) of polyethylene glycol (Mn = 200 g / mole), 0.04 g (5.16 x 10 ^-5 mole) of 1,3,5-trimethyl-2,4,6-tris (3,5-di-ter- butyl-4-hydroxy-benzyl) benzene and 2.75 mg of titanium n-butoxide (IV) in 1.2 g of toluene. The co-polyester obtained in step a) has a number-average molecular weight (Mn) equal to 3200 g / mole, a polydispersity index equal to 2.1, and an iodine number equal to 66 g / 100 g. and a glass transition Tg of -20 ° C.

The characteristics of the crosslinked product are given in Table 1.

Table 1

EXAMPLE 3

Adhesive compositions 1-1-3 and 2.1 are used to make adhesive papers.

The adhesive compositions have a life of at least 24 hours (stable viscosity during this period).

A first layer of the adhesive composition (thickness: 150 μιτι) is applied and abrasive grains are then distributed homogeneously over said layer. The whole is heated at 85 ° C for 15 minutes. Good adhesion of the adhesive layer to the paper and good anchoring of the abrasive grains are observed (these do not come off when subjected to the test of passing the hand on the grain surface).

A second layer of the adhesive composition is applied to cover the abrasive grains and treated at 60 ° C for 50 minutes. The abrasive paper obtained with each of the adhesive compositions tested is devoid of tackiness. The abrasive paper obtained then undergoes an additional heat treatment (post-baking) at 120 ° C. for 2 hours.

It is found that the second layer of adhesive adheres well to the first layer, covers the abrasive grains satisfactorily and maintains them effectively.

In addition, the manual peel test of the abrasive paper shows a cohesive break in the paper with all the adhesive compositions tested, which indicates a very good adhesion of the adhesive composition to the support.

Claims

An aqueous adhesive composition, in particular intended to bind elements composed of natural or synthetic materials, characterized in that it contains at least one water-soluble or water-dispersible unsaturated polyester and at least one ethylenically unsaturated monomer, said unsaturated polyester being obtained by co-polymerization (A) of at least one monomeric or oligomeric polyol, (B) at least one unsaturated polycarboxylic acid or unsaturated acid anhydride and (C) at least one water-soluble polymer containing at least one two hydroxyl, amine and / or epoxy reactive functions.

2. Composition according to claim 1, characterized in that it contains at least 20% by weight of water, preferably at most 70% and more preferably 40 to 60%.

3. Composition according to claim 1 or 2, characterized in that the polyol comprises at most 35 hydroxyl functions, preferably at most 15.

4. Composition according to one of claims 1 to 3, characterized in that the oligomeric polyol comprises at most 10 monomer residues polyols and preferably at most 4.

5. Composition according to one of claims 1 to 4, characterized in that the polyol is chosen from saccharides, 1,3-propanediol and 1,4-butanediol.

6. Composition according to claim 5, characterized in that the saccharide is a monosaccharide, preferably containing 3 to 8 carbon atoms, in particular a hexose or an oligosaccharide.

7. Composition according to claim 6, characterized in that the monosaccharide is glucose, mannose, galactose, a derivative of these hexoses in the form of alicyclic alcohol or a dehydrated derivative of this alicyclic alcohol such as isosorbide, and the oligosaccharide is maltose, cellobiose, lactose, sucrose, trehalose, raffinose, stachyose or dextrin.

8. Composition according to one of claims 1 to 7, characterized in that the unsaturated polycarboxylic acid comprises at least two functions carboxylic acids, preferably at most four, and advantageously at most three carboxylic functions, and at least one ethylenic unsaturation.

9. A composition according to claim 8, characterized in that the unsaturated polycarboxylic acid is a linear or branched aliphatic acid, such as fumaric acid, itaconic acid, maleic acid, traumatic acid, mesaconic acid, citraconic acid and aconitic acid, a cyclic acid such as 2,5-furan dicarboxylic acid (dehydroucic acid) or an aromatic acid such as phthalic acid, tetrahydrophthalic acid, isophthalic acid, terephthalic acid, trimesic acid or pyromellitic acid.

10. Composition according to one of claims 1 to 9, characterized in that the unsaturated polycarboxylic acid and the unsaturated acid anhydride are monomeric.

11. Composition according to one of claims 1 to 10, characterized in that the water-soluble polymer (C) is selected from the group consisting of poly (oxyalkylenes), polyvinylpyrrolidones, polyethyleneimines and polyoxazolines.

12. Composition according to claim 1 1, characterized in that the water-soluble polymer (C) is a polyethylene glycol having a molar mass less than or equal to 600 g / mol and preferably greater than or equal to 200 g / mol.

13. Composition according to claim 1 1, characterized in that the polymer (C) comprises at least 4 monomer units.

14. Composition according to one of claims 1 to 13, characterized in that the unsaturated polyester has a ratio of the number of equivalent hydroxyl functions, amine and epoxy) to the number of equivalent carboxylic functions which varies from 1, 01 / 1 to 2/1, preferably 1, 05/1 to 1, 5/1 and more preferably 1, 10/1 to 1, 2/1.

15. Composition according to one of claims 1 to 14, characterized in that the percentage of the number of monomer units of the polymer (C) to the total number of monomer units of the polyol (A) and the polymer (C) varies from 70 to 95% and preferably 70 to 85%.

16. Composition according to one of claims 1 to 15, characterized in that the unsaturated polyester is a co-polyester of isosorbide, maleic anhydride and polyethylene glycol.

17. Composition according to one of claims 1 to 16, characterized in that the ethylenically unsaturated monomer is chosen from the group consisting of (meth) acrylic acids and (meth) acrylates, methacrylamide, N-vinylpyrrolidone and the unsaturated carboxylic acids.

18. A composition according to claim 17, characterized in that the ethylenically unsaturated monomer is 2-hydroxyethyl methacrylate, itaconic acid, citraconic acid, maleic anhydride.

19. Composition according to one of claims 1 to 18, characterized in that the ethylenically unsaturated monomer is soluble in water.

20. Composition according to one of claims 1 to 19, characterized in that the weight ratio of the ethylenically unsaturated monomer to co-polyester ranges from 1/10 to 1/1 and preferably 1/3 to 1/1.

21. Composition according to one of claims 1 to 20, characterized in that it further contains a free radical initiator selected from peroxides, including 2-butanone peroxide, persulfates and azobisisobutyronitrile (AIBN).

22. Composition according to claim 21, characterized in that the amount of free radical initiator represents 0.5 to 2% of the total weight of the unsaturated co-polyester and the ethylenically unsaturated monomer.

23. Applied abrasive article containing abrasive particles bonded by an adhesive composition according to one of claims 1 to 22.

24. Article according to claim 23, characterized in that it is an abrasive whose support is made of a paper or a fabric based on cotton, polyester or a mixture of cotton and of polyester.