FI76107B - MODIFICATIONS FOR THE USE OF SILL TILLSATSMEDEL I ETT BINDEMEDEL OCH DESS ANVAENDNING. - Google Patents

Abstract

1. Claims for the Contracting States : DE, FR, GB, IT, NL, SE Modifying agent for addition to a binder that is synthesized from a condensation product of (a) formaldehyde and (b) urea, melamine or phenol or a mixture of two or three of these components, characterized in that the modifying agent contains formals of pentaerythritol and dipentaerythritol, methylethers of pentaerythritol and dipentaerythritol and free pentaerythritol. 1. Claims for the Contracting State : AT Use of a modifying agent that contains formals of pentaerythritol and dipentaerythritol, methylethers of pentaerythritol and dipentaerythritol and free pentaerythritol, as a modifying agent for addition to a binder that is synthesized from a condensation product of (a) formaldehyde and (b) urea, melamine or phenol or a mixture of two or three of these components.

Description

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This invention relates to a modifier used in a binder based on a condensation product of (a) formaldehyde and (b) urea, melamine or phenol or a mixture of two or three such compounds, and to the use of such a modifier.

The reaction products of formaldehyde and a mixture of urea, melamine or phenol 10 or these and other similar substances, e.g. guanamines or amides, have been used for several years together with reinforcing or filler materials, e.g. for the manufacture of laminated products.

The technology used is well known and generally means that an aqueous solution of formaldehyde is reacted with a selected substance to form a low molecular weight, soluble compound which, in dissolved form, is combined to strengthen! with the filler, after which the solvent is evaporated. This semi-finished product is then formed into a finished product under pressure 20 and heat. At this stage of the process, a low molecular weight formaldehyde-based binder undergoes a polycondensation reaction which converts the binder into a three-dimensional high molecular weight substance with excellent chemical and physical properties.

An essential step in this process is that the small molecule binder melts and transforms into a fluid phase before the growth of the molecules begins. This is a prerequisite for the final product to achieve the properties that are essential, e.g. dimensional stability.

Flowability in the molding and curing steps is affected by a number of factors. More important are the ratio between the amounts of binder and the reinforcing material or filler, the moisture content of the mixture, as well as the melting point of the binder, the melt viscosity and the curing rate under the selected conditions.

The most important formation conditions are formation pressure, temperature range and formation time. When a high forming pressure is used, satisfactory flexibility can be achieved even with its relatively small amounts of binder and low moisture content using a suitable temperature range. If the formation pressure is reduced, other factors affecting fluidity must be changed in order to maintain the effects of fluidity. The forming process in the manufacture of laminated products is traditionally performed in two different ways. According to the second, the material is introduced into a cold press, after which the pressure is increased and heat is supplied. The temperature is then lowered and the pressure is released. According to another method, the material is fed to a hot press, after which the pressure is raised and finally released without cooling. Both procedures involve compression and molding of the material as well as melting and curing of the binder.

15 The method of producing the finished product without cooling offers great economic advantages compared to the former method, partly due to lower energy consumption, partly due to large time savings.

Recently, there has been technical development from 20 static laminate presses that operate intermittently to continuous belt presses to produce planar thermoplastic laminates. Continuous strip presses for laminates most often operate at significantly lower pressures, at about 10-25 25 bar compared to 1Q0 bar and with shorter pressing times, at about 1/30 to 1/300 of the time required by a cooled static press. .

Compared to a conventional compression cycle with cooling, a static press requires a significantly better flowability and substantially higher reactivity of the binder in a continuous press. These two characteristics are opposite to each other. Namely, the rapid increase in molecular weight shortens the casting time. One method of solving this problem is to increase the binder content relative to the reinforcing material and to increase the moisture content of the material before it is molded and cured. However, this method incurs unnecessarily high costs and the finished product acquires unfavorable properties, e.g. great fragility.

The present invention has made it possible to solve the above-mentioned problems. The invention relates to a modifier for use as an additive in a binder, which binder is based on a condensation product of a) formaldehyde and b) urea, melamine or phenol or a mixture of two or three such compounds. The invention is characterized in that the substance consists of a reaction product obtained by a basic reaction between formaldehyde and acetaldehyde in a molar ratio of 3 to 6: 1, containing 30 to 70% by weight of a mixture of formal forms of pentaerythritol and dipentaerythritol and 5 to 35% by weight of pereerythritol 0.5 to 15% by weight of free pentaerythritol and the rest are various aldol condensation products.

The binder may consist of melamine-formaldehyde resin, urea-formaldehyde resin, phenol-formaldehyde-resin, urea-melamine-formaldehyde resin, urea-phenol-formaldehyde resin, melamine-phenol-formaldehyde resin or urea-melamine-formaldehyde-resin-phenamine. These resins may also contain e.g. toluenesulfonamide, lactams, guanamines, amides, or other additions that improve the properties of the resins.

Resins are prepared according to methods well known and described in the literature.

The invention also relates to the use of the modifier described above as an additive in a binder based on a condensation product of a) formaldehyde and b) urea, melamine or phenol or a mixture of two or three such compounds, the modifier being present in an amount of 5 to 60% by weight based on dry binder.

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The modifier may be added to the binder before, during or after the synthesis of the binder.

When a binder is used to impregnate continuous webs of fibrous material such as paper, a hardener is added to the binder.

The invention will be described in more detail in connection with the following working examples, in which Example 1 shows the preparation of a urea-formaldehyde resin containing a modifier according to the invention and the use of resin for the production of a decorative high-pressure laminate. Example 2 shows the preparation of a melamine-formaldehyde resin mixed with a modifier according to the invention and the use of the resin for the continuous production of a laminate. Example 3 shows the preparation of a mela-15 mine-formaldehyde resin condensed together with a modifier according to the invention, as well as the use of the resin for continuous laminate preparation. Finally, Example 4 shows the preparation of a urea-melamine-formal dehydrate resin condensed together with a modifier according to the invention, as well as the use of the resin for continuous laminate preparation.

Example 1

The reaction vessel was charged with 53.11 parts by weight of 50% formalin, 38.86 parts by weight of phenol and 7.23 parts by weight of a modifier according to the invention containing:

45% by weight of formalities for monopentaerythritol and dipentaerythritol

Miscellaneous aldol condensation products 24% by weight 30 Monopentaerythritol and dipentaerythritol 14% by weight methyl ethers

Free pentaerythritol 7% by weight

Sodium formate 0.5% by weight

Another 9.5 wt% 35 pH was adjusted to about 7.5 and the mixture was heated to reflux. Sodium hydroxide was charged continuously during refluxing for about 35 minutes. The mixture was then cooled, after which additional sodium hydroxide was charged. A total of 1.4% by weight of sodium hydroxide based on phenol was added.

16.81 parts by weight of water were distilled off in vacuo at about 60 ° C. 5.0 parts by weight of methanol and 7.84 parts by weight of urea were then charged at 60 °. After the urea had dissolved, the reaction mixture was cooled.

The prepared water-dissolved resin had the following properties:

Dry matter content 65%

Viscosity 180 cP

pH 8.4

Curing time 150 s at 150 ° C 15 (stroke Cure time) 2

Kraft paper having a basis weight of 150 g / m 2 was impregnated with a resin solution to a resin content of 28% and a curing loss of 7%. Five pieces of such 20-sheet impregnated kraft paper sheets and two pieces of decorative paper surface sheets impregnated with melamine resin were pressed into a laminate in a conventional high-pressure press. A satisfactory laminate was obtained which had to be accepted according to ISO 4586.

Example 2 25.5 parts by weight of 50% formalin, 24.5 parts by weight of water, 0.6 parts by weight of triethanolamine, 1.3 parts by weight of toluenesulfonamide and 29.2 parts by weight of melamine were charged to a reaction vessel. The pH was adjusted to 9.7 and the mixture was heated to reflux.

After refluxing for 10 minutes, the mixture was cooled to 90 ° C, after which the reaction was allowed to continue until a precipitate formed, at which time 1.9 ml of water was added to 35 l of a lacquer sample at 25 ° C. The reaction mixture was then cooled to room temperature, after which 8.9 parts by weight of a modifier of the invention containing

Sodium formate 0.2% by weight

Free pentaerythritol 6.8% by weight 5 Formalities of monopentaerythritol and dipenta-46.1% by weight of erythritol

Free dipentaerythritol 1.0% by weight

14.4% by weight of methyl ether of monopentaerythritol and dipene

Semi-formal 2.3 weight percent

Other aldol condensation products- 27.2% by weight of roads

Water 2.0% by weight 15

The prepared water-dissolved resin had the following properties:

Dry matter content 50.5%

Viscosity 30 cP

20 pH 9.6

Curing time 220 s at 150 ° C (stroke curing time)

After the addition of 1.1% paratoluenesulfonic acid, the pH dropped to 6.9 and the reactivity increased to a stroke cure time of only 27 seconds.

Two different grades of kraft paper having a basis weight of 80 g / m 2 and 150 g / m 2 were impregnated with a resin solution to a resin content of 50% and a cure loss of 30.5%.

The two base paper webs thus obtained were pressed into a laminate having a thickness of 0.6 mm in a continuous double-belt press with a surface-laminated decorative sheet impregnated with melamine resin and a background parchment paper. The compression pressure was 13 bar, the belt temperature 160 ° C and the belt speed 8 m / min.

7 76107 The laminate thus obtained was well cured and had the excellent physical properties mentioned below.

Thermal test, boiler 180 ° C, 20 minutes: approved 5 Impact resistance according to DIN: 18/4 N Blistering temperature: 190 ° C Dimensional stability according to ISO longitudinal: 4/5 per cent transverse: 11 per cent 10 Formability, radius 6 mm, 145 ° C: passed Water soup test, 15 minutes: passed

Example 3 218 parts by weight of 50% formalin, 180 parts by weight of the modifier described in Example 2, 321 parts by weight of water and 3.6 parts by weight of triethanolamine were mixed together in a reaction vessel. The pH was adjusted to 9.8 with sodium hydroxide solution, followed by the addition of 12 parts by weight of p-toluenesulfonamide and 264 parts by weight of melamine.

The reaction mixture was heated to 85 ° C, after which the pH was adjusted to 10.1 with sodium hydroxide. The temperature was then kept constant at 85 ° C for about 2.5 hours. When the miscibility of the resin in water fell below 2 ml of water / g of resin at room temperature, an additional 1.5 parts by weight of 25 parts by weight of triethanolamine were added, after which the whole mixture was cooled to room temperature.

The prepared water-dissolved resin had the following properties:

Dry matter content 49.2%

30 Viscosity 28 cP

pH 9.6

Cure time 240 s at 150 ° C (stroke Cure time).

35 After the addition of 1.1% paratoluenesulfonic acid, the pH dropped to 6.9 and the reactivity increased to a stroke cure time of only 27 seconds.

Two kraft papers of different grades with a basis weight of 80 g / m 2 and 150 g / m 2 were impregnated with a resin-5 solution to a resin content of 51.3% and a cure loss of 9.5% and a resin content of 50.8% and 9.7%, respectively. percent curing loss.

The two base paper webs thus obtained were pressed into a laminate having a thickness of 0.6 mm in a continuous double-strip press with a surface-coated decorative sheet impregnated with melamine resin and a background parchment paper. The compression pressure was 13.5 bar, the belt temperature 155 ° C and the belt speed 7.3 m / min.

The laminate thus obtained was well cured and had the following excellent physical properties. Thermal test, boiler 180 ° C, 20 minutes: approved Impact resistance according to DIN: 18.8 N

Blistering temperature: 190 ° C

Dimensional stability according to ISO 20 longitudinal: 4.5 per cent transverse: 11 per cent Formability, 6 mm radius, 145 ° C: approved Water cooking test 15 minutes: approved

Example 4 34.65 parts by weight of 50% formalin, 18.63 parts by weight of water, 6.50 parts by weight of the modifier described in Example 2, 4.55 parts by weight of isobutanol and 0.36 parts by weight of triethanolamine were charged to the reaction mixture. vessel with. The pH was adjusted to 9.1.

8.25 parts by weight of urea were added, after which the mixture was heated to 80 ° C. After 30 minutes at this temperature, 17.31 parts by weight of melamine were charged. After a further 30 minutes, 8.25 parts by weight of urea were charged, after which the temperature was lowered to 65 ° C. Throughout the 35 reactions, the pH was maintained at least 8.6 with sodium hydroxide.

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The condensation continued at 65 ° C until the miscibility with water at 25 ° C was below 4 ml / g of resin. Then, 1.0 part by weight of triethanolamine was charged, after which the reaction mixture was cooled.

5 The prepared water-dissolved resin had the following properties.

Dry matter content 50%

Viscosity 30 cP

pH 9 10

The reactivity was adjusted with 1.4% paratoluenesulfonic acid to give a stroke cure time of 28 seconds.

Unbleached kraft paper having a basis weight of 2 to 15 g / m 2 was impregnated with the prepared resin solution to a resin content of 50% and a cure loss of 9%. The three base paper webs thus obtained were pressed with a surface-laminated decorative sheet impregnated with melamine resin and a background of parchment paper in a continuous double-strip press into a laminate having a thickness of 0.6 mm. The compression pressure was 12 bar, the belt temperature 150 ° C and the belt speed 7 m / min.

The laminate thus obtained was well cured and had the following excellent physical properties.

Thermal test, boiler, 180 ° C, 20 min: approved Impact resistance according to DIN: 17.5 N 1/4 Necking temperature: 180 ° C 30 Longitudinal dimensional stability: 4 per cent transverse: 10 per cent Water cooking test 15 minutes: approved.

Claims (2)

A modifier for use as an additive in a binder, which binder is based on a condensation product of a) formaldehyde and 5 b) urea, melamine or phenol or a mixture of two or three such compounds, characterized in that the substance consists of a basic reaction between formaldehyde and acetaldehyde in a molar ratio of 3 to 6: 1 of the reaction product obtained, containing 30 to 70% by weight of a mixture of formal forms of pentaerythritol and dipentaerythritol, 5 to 35% by weight of a mixture of methyl ethers of pentaerythritol and dipentaerythritol and 0.5 to 15% by weight of free pentaerythritol and final alpha-erythritol -15 roads. Use of a modifier according to claim 1 as an additive in a binder based on a condensation product of a) formaldehyde and b) urea, melamine or phenol or two or three such compounds, the modifier being present in an amount of 5 to 60% by weight based on the dry binder.