SK4092002A3 - Binding agent for producing shaped bodies and use of said agent - Google Patents

Abstract

The invention relates to a binding agent for producing shaped bodies and to shaped bodies produced by using said binding agent which is provided with a content of A) a polymer of 0 to 50 wt. % of at least one ethylenically unsaturated dicarboxylic acid, the anhydrides thereof and/or the salts thereof and 50 to 100 wt. % of at least one ethylenically unsaturated monocarboxylic acid, B) at least one armine that can contain less than two OH groups and is present in an amount so that the pH value of the binding agent ranges from 2 to 7, C) 0.5 to 30 wt. % in relation to solid bodies (A+B) of a cross-linking agent on epoxide or acrylate resin basis and optionally and additionally one polyol with at least two OH groups in an amount of up to 20 wt. % in relation to solid bodies. The shaped bodies that are produced by using said binding agent can be produced in lower temperatures and involving shorter production times and are provided with an improved hygrostability.

Description

Fasteners are required to produce molded products from natural or synthetic fine-grained or fibrous materials.

BACKGROUND OF THE INVENTION

Phenol-formaldehyde resins, melamine-formaldehyde resins, furfurol resins, aminoplasts or starches are commonly used as binding agents for such shaped articles. These known products either have the disadvantage that they release volatile low-molecular components of the binder, such as formaldehyde, over time, or that they do not maintain shape stability under increased atmospheric humidity.

In order to overcome this drawback, a binder is used in EP 0 445 578 B1 which comprises an aqueous mixture of at least one high molecular weight polycarboxylic acid and at least one polyhydric amine, alkanolamine or polyhydric alcohol in dissolved or dispersed form. To produce the corresponding shaped article, fine-grained materials consisting of the shaped article (e.g., wood chips) are mixed with an aqueous binder solution, the resulting slurry is formed and dried at a temperature of 100 to 250 ° C while drying the polycarboxylic acid condensation reaction with the amine. , or a polyhydric alcohol to form esters or amide formation.

In order to improve the watertightness of the molded article described in EP 0445 578 B1, DE 196 06 393 A1 discloses a fastener for fibers, pulp or chips comprising:

A) a polymerizate obtained by radical polymerization, which may consist of 5 to 100 wt. from ethylenically unsaturated acid anhydride, or

31904 / H ethylenically unsaturated dicarboxylic acid, the acidic carboxyl groups of which form an anhydride group, such as

B) an alkanolamine having at least two hydroxyl groups.

In addition to the ethylenically unsaturated monomer based on an unsaturated dicarboxylic acid, the polymerizate A) may contain further monomers such as an unsaturated monocarboxylic acid, an olefin, or another derivative of an unsaturated monocarboxylic acid such as an amide.

Also known from EP 0 583 086 B1 are formaldehyde-free aqueous fasteners for the production of mechanically stable heat-resistant glass fiber webs. The fastener comprises

(a) polyacids with at least two carboxyl groups; their anhydrides or their salts,

b) polyols with at least two OH groups

(c) a phosphorus-containing reaction accelerator.

As a polyacid, a polymeric polyacid such as e.g. polyacrylic acid.

Amine-containing polyols containing at least two OH-groups can also be used as polyols. Preferably, a special polyol, namely - [N, N-di (p) hydroxyethyl] -adipamide, is used. The carboxyl groups of the polycarboxylic acids are neutralized to less than 35% by a nonvolatile base such as e.g. NaOH.

In EP 0 651 088 A1, in principle, the same fasteners as in EP 0 583 086 B1 are used for strengthening or securing. reinforcement of cellulose-based substrates.

DE 197 29 161 A1 also describes formaldehyde-free aqueous fasteners for shaped articles such as fibreboard or particle board, which allow processing at low temperatures and the substrate can provide water tightness. The binding agent comprises at least one polymerizate (A1) containing 0 to 5 wt. of one α, β-ethylenically unsaturated co-polymerized mono- or dicarboxylic acid and can be obtained by radical polymerization

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a) at least one radical polymerization of the recoverable polymer (A2) comprising 15 to 100 wt. one α, β - ethylenically unsaturated mono or dicarboxylic acid; and

(b) at least one amine containing at least one long chain of at least six carbon atoms, the ratio by weight (solid phase) of polymer (A1) to polymer (A2) being in the range of 7: 1 to 1: 7 and the weight ratio The polymer of the (A2) to the long chain amine lies in the region. from 20: 1 to 2: 1. Long chain amines are those having at least 6 carbon atoms, in particular 6 to 22 carbon atoms in alkyl, or alkenylamine, and which may also contain hydroxyl groups. In addition to long chain amines, alkanolamines with at least two hydroxyl groups can also be used. The production of such systems in which a combination of two polymerisates is involved is complicated, wherein the production of a polymer having a lower acid number is carried out in the presence of a polymer having a higher acid number.

DE 44 08 688 A1 describes bonding, impregnating or coating means for the production of fibrous sheets based on artificial, mineral and glass fibers containing

A) a polymerizate formed from 2 to 100 wt. from ethylenically unsaturated acid or acid anhydride as a comonomer; and

B) at least one special polyol selected from the group of triazines, triazinetriones substituted with benzene or cyclohexene-derived polyols, aliphatic polyols containing one tertiary amino group, or hydroxyl groups containing phosphorous, boric or phosphoric acid derivatives.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to improve known fasteners with respect to water tightness, processing temperatures and processing duration.

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Surprisingly, it has been found that this task can be solved by an aqueous solution or dispersion-based fastener, wherein the fastener comprises

(A) a polymerizate consisting of

1) 0 to 50 wt. % preferably 5 to 40 wt. at least one ethylenically unsaturated dicarboxylic acid

2.) 50 to 100 wt. %, preferably 60 to 95 wt. % of at least one ethylenically unsaturated monocarboxylic acid; The acidic ethylenically unsaturated monomers may be replaced by other ethylenically unsaturated monomers, preferably water-soluble monomers.

and

B) an aliphatic, aromatic or heterocyclic amine which, as functional groups, may contain, in addition to amino groups, less than two OH groups, in an amount such that the pH of the coupling agent lies in the range of from 7 to 7, preferably from 2 to 4;

C) 0.5 to 30% by weight. %, preferably from 1 to 15 wt. based on the solid phase (A + B) of an epoxy or acrylate resin crosslinker,

Further, the binder composition of the invention based on solid phase [(A + B)] may comprise at least one organic compound with at least two hydroxyl groups per molecule, preferably an aliphatic polyol with at least two OH groups. The compound with at least two OH groups, based on solid phase [(A + B)], can be used in an amount of from 0 to 20% by weight, preferably 5 to 15% by weight, based on the solid.

Polymerizate component A is preferably produced by free-radical polymerization by known methods. Preference is given to solution polymerization with

31904 / H with water as the solvent. This can be a homopolymer of ethylenically unsaturated monocarboxylic acid or a copolymer of ethylenically unsaturated monocarboxylic acids with ethylenically unsaturated dicarboxylic acids. Also suitable as monocarboxylic acids are their salts, in particular amines or ammonium salts, as well as dicarboxylic acids, and their anhydrides and / or salts, in particular amines or ammonium salts. Preferred ethylenically unsaturated monocarboxylic acids are acrylic, methacrylic, vinylacetic and / or crotonic acid. Preferably, dicarboxylic acids such as maleic acid, 2-methylmaleic acid, fumaric acid, itaconic acid, 2-methylitaconic acid, tetrahydrophthalic acid, and anhydrides and salts thereof are used, as well as semi-esters of dicarboxylic acids, especially monoalkyl esters, monoalkyl maleate and monoalkyl fumarate. Mono- and dicarboxylic acids and / or derivatives thereof which are soluble in water are preferred. Conventional additives such as known molecular weight modifiers, for example mercaptans, such as 2-mercaptopropionic acid, or disulphites, such as sodium metabisulphite, or compounds which are both esterification catalysts and molecular weight modifiers, such as hypophosphites, for example sodium hypophosphite, are used. Preferred polymerisates have a molecular weight in the range of 50,000 to 200,000.

Polymerisate A may contain, in addition to the main components of said acidic monomers, up to 10% by weight, based on the sum of the acidic monomers, other ethylenically unsaturated monomers, such as a vinyl ester, for example vinyl acetate or an acrylic ester, or acrylamide. Preferably, these monomers are water-soluble or water-miscible.

The carboxyl groups in Polymer A are partially neutralized in the coupling agent, typically from 5 to 20 mol%. The acid groups are neutralized.

Amine components B, which may be primary, secondary or tertiary, or mixtures of these amines, serve to neutralize. Preferred amines are diethanolamine, diisopropylethanolamine, triethylamine, 1-methylimidazole as well as polyamine, for example ethylenediamine.

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The amine is added to the polymer in an amount to ensure that the resulting binding agent has a pH in the range of 2 to 7.

The crosslinking agent (component G) used is epoxy, acrylate or resorcinol resins, for example the known water-borne epoxy resins based on bisphenol A or diacrylate. The amount of component C, based on the resin, is 0.5 to 30% by weight, preferably up to 15% by weight.

The binder may comprise other components, such as polyhydric alcohols with at least two hydroxyl groups. Suitable polyols are glycerin, glycol, trimethylolpropane, butanediol, pentaerythritol, sorbitol, polyvinyl alcohol, mono-, oligo- and polysaccharides such as glucose or hydroxyethylcellulose, which are used in amounts up to 20% by weight, preferably 5 to 15% by weight. based on the resin.

The production of the fasteners according to the invention is carried out by mixing the components. The binding agent is an aqueous solution that is storage stable.

According to a preferred embodiment of the invention, the binder composition may further comprise monomers, i. % unsaturated unsaturated dicarboxylic acids in an amount of up to 30 wt. %, preferably from 5 to 20% by weight, based on the sum of the monomers A1 and A2 used. The content of unpolymerized unsaturated dicarboxylic acids can be achieved by admixing the polymer or by controlling polymerization.

Surprisingly, the fastener according to the invention has achieved a significant improvement in the watertightness as well as a decrease in the curing temperature during the production of the reinforced substrates by the fastener according to the invention, whereby the time required for manufacture is greatly reduced.

To produce shaped articles, the fastener is mixed in a conventional manner with the reinforced substrate, preferably by spraying a fibrous substrate such as wood chips or cellulose fibers. After spraying the substrate with the binding agent, it is at a temperature of from 60 to 150 [deg.] C. up to a residual moisture content of from 10 to 15% by weight. and then

By the method 31904 / H, a blank (preform) comprising a fastener, for example a web, is produced which is finally cured at a curing temperature of, for example, 180 to 240 ° C. The proportions of the amount of binding agent in the reinforced substrate are in the range of 1 to 10% by weight. a dry fastener, based on the fine-grained or fibrous material.

In the following examples, all parts are by weight.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Polyacids made of 70% and a 30% mass (30% solution) _(Mw 180 000 g / mol; pH value 0.8) 100 p Dimethylethanolamine 4 T 2 T glycerin

Siquest A 187 (Witco) 0.3 T

Mixing gives a clear solution (pH value 2,1)

Example 2

Polyacids made of 80% AS and 20% MAS as a 30% solution (M _w 105 000 g / mol; pH value 0,9) 100 T dimethylethanolamine 3

CN 132 (Cray Valley) 2 T

Mixing of the components gives a clear solution (pH value 3.5)

Example 3

Polyacids made of 100% AS 30% aqueous solution _(Mw 120 000 g / mol; pH value 1.8) 100 p Dimethylethanolamine 2.5 T

Alberdingk EP 70 0.5 T

31904 / H glycerin

A clear solution is formed (pH-value 3.3)

Example 4

Pure polyacrylic acid as a 30% aqueous solution

3,5 T (M _w 175 000 g / mol; pH 1,8) 100 T is combined with dimethylethanolamine 4 T glycerine 2 T

Siquestom A 187 (Witco) 0.3 T

To this batch is added maleic anhydride 10 T water 20 T glycerin 0.6 T dimethylethynolamine 1.2 T

Siquest A 187 (Witco) 0.09 T gave a clear solution (pH-value 2.3).

AS - acrylic acid

MAS - maleic acid

Alberdingk EP 70: water-dilutable epoxy resin (based on bisphenol A with epoxy end groups, molecular weight less than 700), manufactured by Alberdingk Boley

CN 132 acrylic resin (oligomeric aliphatic diacrylate), manufacturer: Cray Valley

Siquest A 187: epoxy-functional trimethoxysilane, manufactured by Witco

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Water resistance test by firing fasteners on a glass plate.

The formulations of Examples 1 to 4 were tested for watertightness as follows:

The 150 µm fastener film was spread on a glass plate, dried and baked at 180 ° C for 5 minutes. The glass plate was placed in water and the film was evaluated after 10 minutes, 4 hours and 24 hours. The following scale was used:

1. The film did not change in appearance and scratch resistance.

2. Film appearance unchanged, scratch resistance slightly reduced.

3. Film appearance unchanged, scratch resistance strongly reduced.

4. Film appearance unchanged, film can be scratched off the plate.

5. The film dissolves at the edges.

6. The film creates individual bubbles.

7. The film dissolves to 30%.

8. The film dissolves to 60%.

9. The film dissolves to 90%.

10. - The film has completely dissolved.

The results of the water resistance of the film according to Examples 1 to 3 are summarized in the following table:

Table 1

Example 1 Example 2 Example Example 4 waterproof after 24 hours 1 3-4 2-3 1

In further experiments, the fastener according to the invention was compared with the product Acrodur DS 3495 according to DE 196 with respect to its water tightness.

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393 Α1 (BASF) at different film firing times (depending on the curing time in the production of shaped articles), both at the same firing temperature but different film firing times and at the same firing time but different firing temperatures. (The firing temperature corresponds to the curing temperature in the manufacture of the shaped article, i.e., in the manufacture of the particle board. The firing time corresponds to the curing time or the pressing time, respectively). The results are shown in Figures 1 to 2; 1 according to the invention.

Description of the drawings

In Figure 1, it is shown that with a firing time of less than 3 minutes, the product according to the invention exhibits excellent waterproofness, while the prior art product has a completely insufficient waterproofing. . It is only at substantially longer firing times than 4 minutes that the water-tightness of both products is comparable. It is to be understood here that the longer firing time in the continuous production of a molded plate means a substantial increase in the production time, otherwise expressed by the production of the product according to the invention, a significant reduction in the production cycle time in the production process.

It can be seen from Figure 2 that the product according to the invention, in particular at low firing temperatures (corresponding to the curing temperatures in the production of shaped articles), significantly exceeds the known products. Thus, according to the invention, the product according to the invention exhibits an excellent watertightness (2) at a firing temperature of 200 [deg.] C., whereas at this firing temperature the prior art product has a completely unsatisfactory value (10). It is only at a baking temperature of 220 ° C that the prior art product achieves the same waterproofness as the product according to the invention.

In further experiments, mechanical properties (bending resistance, E-modulus of bending as well as water absorption and swelling thickness) were determined at

31904 / H fibreboard molded boards which were manufactured once using the fastener of the invention and the second time using the commercial product Acrodur DS 3495.

Test procedure and production of fibreboard.

The fibrous material is covered with a fastener on the forming line and dried to a residual moisture of about 7%. Drying is carried out at 60 ° C. The fibers thus coated are processed into mats which are compressed to a thickness of 2 to 3 mm at a temperature of from 180 to 230 ° C. The pressing time was 10 to 30 'seconds.

The following values were measured:

Flexural strength (N / mm ² )

Bending module E (MPA)

Water absorption after 12 hours storage in water (%)

Swelling thickness after 12 hours of storage in water.

In comparative experiments, a mixture of 80% wood and 20% synthetic fibers was used. The coverage amount was 7% by weight. of a fastener (dry matter) based on the fibers.

The results are shown in Table 2.

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Table 2

Tool temperature / pressing time measured values Acrodur DS 3495 Example 1 AC7591 230 ° C / 20 + 20 sec , flexural strength j (N / mm ² ) 52.4 56.5 flexural modulus E (MPA) 3172 . 3643 water absorption (%) 57.4 47.3 swelling thickness (%) 21.5 18.9 200 ° C / 20 + 20 sec. flexural strength bubble formation 56.5 (N / mm ² ) further measurement flexural modulus E not possible 3229 (MPA) water absorption (%) 56.2 swelling thickness (%) 17.6 180 ° C / 20 + 20 sec. flexural strength (N / mm ² ) - I 56.5 flexural modulus E (MPA) 3548 s water absorption (%) swelling thickness 69.7 ! (%) 19.6 180 ° C / 10 + 10 sec. ' flexural strength (N / mm ² ) • 49.3 s flexural modulus E 2951 (MPA) water absorption (%) swelling thickness 68.8 I I and J (%) 26.1

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It can be seen from Table 2 that the product according to the invention has a superiority over commercial products at a pressing temperature of 230 [deg.] C., particularly advantageous is the product according to the invention in ° C and below, where a prior art product due to the formation of bubbles is excluded from further testing. (For bubble formation, refer to the above scale from 1 to 10 in the watertightness test, see 6 at which individual bubbles begin to form).

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Claims (17)

à f W '£ θΰλ / Joint compound for the production of shaped articles of natural or synthetic fine-grained or fibrous materials, characterized in that it comprises: (A) a polymerizate consisting of 1) 0 to 50 wt. at least one ethylenically unsaturated dicarboxylic acid, anhydrides and / or salts thereof 2.) 50 to 100 wt. % of at least one ethylenically unsaturated monocarboxylic acid and / or salts thereof, wherein up to 10 wt. the acid ethylenically unsaturated monomers may be replaced by other ethylenically unsaturated monomers copolymerizable with acid ethylenically unsaturated monomers, preferably water-soluble monomers, and B) at least one amine, which may contain less than two OH groups, in an amount such that the pH of the binder is in the range of 2 to 7. C) 0.5 to 30 wt. , preferably from 1 to 15 wt%, based on solid phase (A + B); a crosslinking agent based on an epoxy or acrylate resin, The binder of claim 1, further comprising at least one compound having at least two hydroxyl groups per molecule; preferably a polyol with at least two OH groups, in an amount of from 0 to 20% by weight, preferably 5 to 15% by weight, based on the solid. 31904 / H 1-5 Binder according to one of Claims 1 to 2, characterized in that the polymer component A), such as ethylenically unsaturated monocarboxylic acid, contains acrylic acid. Binder according to one of Claims 1 to 3, characterized in that the polymer component A) contains maleic acid as the ethylenically unsaturated dicarboxylic acid. Coupling agent according to claim 1, characterized in that the amine component B) contains a hydroxyl group. Coupling agent according to claim 1, characterized in that the amine component B) is dimethylethanolamine. Coupling agent according to one of Claims 1 to 2, characterized in that the amine component B) is a monovalent or vivacalmous primary, secondary or tertiary amine. Binder according to claim 7, characterized in that the amine component B) is triethylamine. Binder according to claim 7, characterized in that the amine component B) is methylimidazole. Coupling agent according to any one of claims 2 to 9, characterized in that it further comprises an aliphatic polyhydric alcohol, preferably glycerin. The connection means according to any one of claims 1 to 9, characterized in that it is in the form of an aqueous solution or dispersion. 31904 / H Coupling means according to any one of claims 1 to 11, characterized in that it further comprises 0 to 30 wt. %, preferably 5 to 20 wt. based on monomers A1 and A2, a non-polymerizable monomeric dicarboxylic acid. Use of a fastener according to claims 1 to 12, for the production of shaped articles from natural or synthetic fine-grained or fibrous materials. The use of a fastener according to claim 13, characterized in that the fastener is used as a solid product in an amount of 1 to 10% by weight. based on fine-grained or fibrous material. Use of a fastener according to one of Claims 13 to 14, characterized in that wood fibers are used as the fibrous material. A shaped article obtainable by impregnating a substrate based on natural or synthetic fine-grained or fibrous materials with a fastener according to one of claims 1 to 12 and curing the impregnated substrate. The shaped product according to claim 16, wherein the panels are wood and cellulose chips and fibers. 31904 / H Waterproof at 200 ° C firing temperature 1/2 AC 7591 DS 3495 Watertightness r p hW'edd / Waterproof after 3 minutes of baking time on glass 2/2 o about Water resistant temperature