FI64614B - ANALYZING AV GLYCOLDER WITH SOME MODIFICATIONS FOR FENOLHARTSER - Google Patents

Description

I- - »_ ΤΤΊ r_. ANNOUNCEMENT - -, - A

^ UTLÄGGNINGSSKRIFT 6461 4 (45) ^ (51) Kv.Mc.Vet3 C 08 K 5/06, C 08 L 61 / 04- // C 08 G 8/28 FINLAND — FINLAND {21) p «^ n« iMiwi »-P» Mnt * MeimiB * 76377¾ (22) HkmhpiWI-AnriHmlnpd · * 31.12.76 '' (23) AlktipSIvi — Glltighcodag 31.12 76 (41) Tullut futkiMiul - Bllvlt offantftg ^ gy γγ

Patent] * reki * terlh »l! Ttu * / 44) NihtiY» k $ lpanoo and audjullilaun prtn.—

Pstenfe- och registerstyrelsen Ara & kan uttafd och utl. * Kr (ft * n pwbl (eerad 31.0Ö. Ö3 (32) (33) (31) Pyydetty «tuolkaut - priority 12.01.76

Federal Republic of Germany-Forbundsrepubliken Tyskland (DE) P 2600887-7 (71) Th. Goldschmidt AG, Goldschmidtstrasse 100, 1 + 300 Essen,

Federal Republic of Germany-Fröbundsrepubliken Tyskland (DE) (72) Dietmar Schedlitzki, Essen, Holger Vacker, Essen,

German Federal Government of the Republic of Germany (DE) (7¾) Oy Borenius & Co Ab (5¾) Use of glycol derivatives as modifiers for phenolic resins -

An example of a glycolytic modifier is a herbicide for a phenolic resin

Timber boards, especially plywood or plywood boards, are used as concrete boarding boards, which are coated with artificial plastic to allow repeated reuse of these boards. The function of the synthetic plastic coating is then to protect the wooden substrate from the effects of alkali-reactive concrete and to form a smooth outer surface, which is also preserved after many repeated uses.

High performance requirements are placed on the performance of such resins used for coating. They must withstand the corrosive effect of alkali-reactive concrete. In this case, they must seal the base as watertight as possible and maintain this property even at elevated temperatures, since such boards are used to make components from hot concrete with a temperature of up to 70 ° C.

Phenol formaldehyde resins have proven to be useful resins. According to the state of the art (reported, for example, in the journal "Goldschmidt informiert", 1969, no. Phenol-formaldehyde resins having a phenol-to-formaldehyde ratio of 1: 1.3 to 1: 2.5 and prepared using alkali or alkaline earth metal hydroxides in amounts of 0.02 to 0 as catalysts are conventionally used. 2 moles of catalyst per mole of phenol. This solution impregnates mainly sulphate kraft paper, which. 2 papers.no is 20 ... 1 80 g / m, in which case the finished product must contain 50 ... 75% by weight of resin, based on the resin-coated film.

When these films are used in practice, it has been found that one particularly important feature in this case is that the compressed boarding films must not have any superficial cracks, because alkali-reactive water from the concrete slurry otherwise penetrates the slab through these cracks. This causes the board to swell and eventually damage it. At the same time, through these cracks, substances contained in the wood can also penetrate the concrete surface and damage its color.

; The object of the invention is to reduce the formation of cracks or to completely prevent cracks in hardened, coated surfaces.

However, a person skilled in the art is familiar with a number of modifiers for modifying phenol-formaldehyde or urea, melamine-formaldehyde resins. However, some such modifiers are used. to modify compression masses in which the resin is substantially anhydrous. However, since in the present case aqueous solutions of the resin are used to impregnate the paper, the modifiers must also be water-soluble. Some modifiers known per se, on the other hand, are unsuitable because, due to their high-molecular structure, they affect the impregnation of the carrier web with the resin solution. In addition, a particularly important requirement is that, despite the modification of the resins, they must remain stable to the concrete slurry in order to prevent any possible discoloration of the concrete caused by phenol-formaldehyde resin, which would be very disturbing, especially when such boards are used in exposed concrete structures.

s i

It has surprisingly been found that glycol derivatives of the general formula xo (ch2ch2o) xh 3 64614 in which R represents an aliphatic or cycloaliphatic residue having 4 to 6 carbon atoms or a phenyl residue and x is a number in the range 1 to 2 can be used as modifiers for phenolic resins, which resins are used in combination with a carrier for the production of phenolic resin-coated concrete slabs.

Particularly suitably in the formula R is a butyl or isobutyl residue, if R is a cycloaliphatic residue, a cyclohexyl residue is suitably used. Particularly preferably R represents a phenyl residue.

x is an arbitrary number within the limits 1 ... 2, including the values 1 and 2. Suitably the value of x is 1 ... 1.5. If the value of x is between 1 and 2, it is a mixture of compounds, in which case the value of x is an average.

According to the invention, the modifiers can be used at any stage of the preparation of the phenol-formaldehyde precondensate, so that they can be added to the reaction mixture immediately at the beginning of the preparation or at an arbitrary time, and can also be added to the finished precondensate. Upon curing, these modifiers condense on the resin due to the hydroxyl group at the terminal position.

The amount of this modifier to be added is 3 to 20% by weight, based on the solid resin, and the range 5 to 15% by weight is particularly preferred. By impregnating the papers in a manner known per se with such modified phenolic resins and pressing them into sheets of wood, the same curing rates are obtained using surfaces with considerably improved cracking strength. It was particularly surprising to a person skilled in the art that, despite the relatively large addition of the modifier, the durability relative to the concrete did not deteriorate.

With the aid of the modified phenolic resins according to the invention, it is also possible to coat relatively easily cracked plywood boards, e.g. those with softwood plywood as a cover plywood, and these boards can be used repeatedly as concrete boarding boards. As a result, a person skilled in the art can also use inferior slabs to produce reusable resin-coated concrete slabs that can be used repeatedly.

4,64614

The modification of phenolic resins is explained in the following examples and at the same time some operational results are presented.

Example 1

A highly absorbent filled sulphate cellulose paper weighing 80 g / m 2 is impregnated and coated with an aqueous solution of phenol-formaldehyde precondensate according to a method known per se, and then dried, then precondensed at 150 ° C. The final film obtained has a final weight of 200 g / m 2 and a content of volatile components of about 7.5% by weight, which is determined by drying the film for 5 minutes at 160 ° C.

A commercially available aqueous solution of phenol formaldehyde precondensate is prepared in the usual manner by basic condensation of 1 mole of phenol, 1.5 moles of formaldehyde and 0.05 moles of sodium hydroxide at 80-90 ° C. The viscosity at 20 ° C is approx. 50 seconds, measured with an outflow cup according to DIN 53211 (M · mm nozzle).

In case a) the resin is used unmodified "b) at the beginning of the phenolic resin synthesis, 10% by weight of a mixture of 95% phenylglycol CgHg-O-CH2-CH2-OH and 5% phenyldiglycol CgHg-CO-CH2-CH2) 2 ~ ° H» solid is added. (c) at the end of the phenolic resin synthesis, the same amount of modifier mixture is added.

The resulting phenolic resin films are then pressed at 135 ° C using a pressure of 150 N / cm for 15 minutes into 20 mm thick carpentry boards with a bundle middle layer and 2.5 mm thick Meranti plywood on both sides.

To test the cracking strength, the coated sheets are stored for 3 days at 70 ° C, after which they are examined for the presence of cracks. The boards coated with the unmodified phenolic resin according to a) have to a large extent cracks in the length of one centimeter parallel to the fibers of the cover plywood, while the boards coated with the modified resins b) and c) had no cracks.

5,64614

To test the durability of the concrete, freshly mixed concrete with 1 part by weight of cement, 3 parts by weight of sand and 1 part by weight of water is applied to the coated slabs in tanks, after which the slabs are allowed to stand for 16 hours at 90 ° C. The hardened concrete pieces are then removed and examined for corrosion in the film or for a change in the color of the concrete surface.

In all three cases, the surface of the concrete had not changed color and had hardened in the normal way. The corrosion applied to the film is relatively small in all plates. Both results prove that the added modifier does not slow down the curing of the phenolic resin.

Example 2

Highly absorbent unfilled, unbleached sulphate kraft paper weighing 40 g / m 2 is impregnated as described in Example 1 with phenol formaldehyde precondensate to a final weight of 105 g / m 2. The content of liquid components is 6.5% by weight. The same phenolic resin as in Example 1 is used to impregnate the paper, in which case a) unmodified b) 7.5% by weight of butyl glycol C ^ Hg-O-C1-4-Cl2-OH, calculated on the dry weight, is subsequently added to the phenolic resin, c) 7.5% by weight of a mixture of 85% by weight of butyl glycol and 15% by weight of butyl diglycol c4h9- (o-ch2-ch2) 2-oh.

o 2

The phenolic resin films are pressed at 135 ° C and 150 N / cnr pressure for 10 minutes on both sides of 5 mm thick plywood sheets. Plywood boards consist of three cross-glued Douglas pine plywood.

To test the cracking strength, the coated plywood sheets are stored for 3 days at 70 ° C, and after cooling, the presence of cracks is examined.

The plates prepared with the unmodified phenolic resin according to a) had a considerable number of larger cracks, while the plates coated with the modified resins b) and c) showed only a small number of small cracks.