NO138029B - PROCEDURES FOR THE MANUFACTURE OF PHENOLE / ALDEHYDE CONDENSATORS - Google Patents

Description

The present invention relates to a method

for the production of foamed products derived from phenol/aldehyde condensation products. Said foamed plaster is used as insulation and. construction materials in the building and deep-freezing industry, in different types of transport, for insulation

ing of pipelines etc.

A known method for producing foamed plasters based on phenol/aldehyde resins of the novolak type is one which comprises a high-temperature treatment of solid preparations resulting from mixing novolak resin with a foaming agent and hexamethylenetetramine.

The foaming, hardening and shaping of such preparations is carried out in an ammonia-basic medium, where ammonia is released due to the thermal decomposition of hexamethylenetetramine.

Also. known in the art is a method

for the production of foamed substances derived from phenol/aldehyde resins of the resol type, comprising mixing of liquid resols with foaming agent with subsequent expansion, hardening and shaping of the reaction mixture in an acidic medium.

With this method, it is possible to produce foamed plasters by heating the reaction mixture and without supplying external heat.

Each of the above methods is fraught with serious shortcomings.

Thus, a known method for treating novolak resin is characterized at a high temperature and extended molding cycle, because foaming of the preparation is carried out in melt of novolak resins at a temperature of from 100 to 120°C and curing is carried out at a temperature of 140 - 160°C for a period of several hours.-_ In addition to this • the aforementioned method exhibits stationary and batch production determined by the forming cycle of a solid preparation into a foam at a relatively high temperature as well as a complex apparatus which is essential<:>for fine grinding and homogeneous mixing of the solid components of the foam composition.

The low uneconomical yield of these technological methods, the relatively high costs and the limited volume of the finished foam are explained by the aforementioned shortcomings which are characteristic of the known methods for foaming phenol/aldehyde resins of the novolak type.

The accompanying shortcomings of the Tc girl method for the production of phenol/aldehyde foam plaster of the resol type lie in the following: - low chemical activity for the resins during the foaming and a relatively prolonged forming cycle for the foam, especially in constructions and forms made from substances with heat absorption capacity (metals and the like) or at working temperatures below 20°C, - the necessity of adding sufficient amounts of an acidic agent for foaming and hardening of the mixture over a period of several minutes at temperatures below 100°C, which has a determining effect on the corrosion activity for the foamed plasters when they come into contact with a wide spectrum of construction materials that find extensive use in practice, - low stability of "resol" resins during storage and transport (usually several weeks), which prevents their further processing into a foam with apparent low density, especially in the case of on-site foam production.

Next to this, the foamed plasters based on phenol/aldehyde resins of the resol type lag behind the foamed substances derived from novolak resins in terms of moisture and flame resistance.

A method for the production of foam plaster based on a mixture of phenol/aldehyde condensation products of the resol and novolak type is also known (see British patent no.

Such mixtures are foamed and cured in the presence of a foaming agent and. an acid catalyst comprising a mineral acid (eg orthophosphoric acid or sulfuric acid) or an aryl sulphonic acid (eg benzene or phenol sulphonic acid). These acid catalysts remain in the foamed product in a free state and result in a relatively high corrosive effect of the resulting foam plastic when used in conjunction with many traditional construction materials (metals, reinforced concrete, etc.). In addition, the known mixtures of resol and novolak resins have comparatively low foaming and curing activity when processed on continuous units using a high conveyor speed.

It has previously succeeded in reducing the corrosion activity of phenol/aldehyde foam and even apparently eliminating it by replacing the usually used acid catalysts with the products of a cocondensation of arylsulfonic acids with formaldehyde and urea (see French patent no. 1,583,857 ). However, another serious shortcoming of foamed phenols, namely the high brittleness, could not be eliminated.

The purpose of the present invention is to eliminate the shortcomings of the known methods.

The invention is based on a method for the production of foam plastics from phenol/aldehyde condensation products which makes it possible to process products of both the novolak and resol type by rapidly forming a liquid mixture in cavities of practically any geometric shape made from mate- rials with high heat capacity bg low acid resistance. Furthermore, it is possible to carry out the method at temperatures

below 100°C, preferably in a temperature range from 10 to 20°C, during a short period of time, i.e. within seconds or minutes.

The present invention thus relates to a method for producing foam plastic with reduced brittleness and improved strength properties by mixing phenol/aldehyde resols and/or aldehydes with phenol/aldehyde novolacs and possibly additives, foaming and curing of the mixture by acid catalysis, and the method is characterized by the fact that core sulfonated phenol/aldehyde novolaks are mixed in as Jiovolak, : the weight ratio between the Jicjemesulfonated novolaks and the resols is from 85:15 to 15:85, calculated on the weight of dry matter, while the weight ratio between core sulfonated novolaks and aldehyde is from 95:_5 to 60:40, calculated on the weight of dry matter.

Preferably, floateride<e>"pheno1/aldehyde-novo-lac resins are used as core sulfonated phenol/aldehyde condensation products in combination with condensation products - of arylsulfonic acids with aldehydes. The use of such products makes it possible to obtain a foam plastic with a significantly reduced corrosive effect .

Furthermore, it is advantageous that organic nitrogen-containing compounds are added to the mixture in the form of individual compounds or mixtures thereof or in the form of reaction products. with arylsulfonic acids and/or aldehydes. In addition to the nitrogen-containing compounds blocking the sulfo groups in the aromatic sulfonic acid during the reaction with formaldehyde, it also plays a role as an acceptor for formaldehyde,

and thereby improves the working conditions during local production of the foam plastic.

The proposed method for producing phenol/aldehyde foam further provides the following advantages, compared to known methods. It allows liquid reaction mixtures that foam and harden upon moderate heating (below 100°C) or without the application of external heat, to be processed into a plastic foam by rapid forming.

It also makes it possible to produce foamed plasters based on phenol/aldehyde condensation products of both the resol and novolak type using continuous and semi-continuous equipment for forming the foams. Furthermore, the method described largely solves the problem by processing the phenol/aldehyde condensation products into high-quality foam practically without regard to the time of production of the condensation products.

This latter makes it possible to transfer the leather production from the phenol/aldehyde resin supply warehouse to distant locations for use.

Phenol/aldehyde condensation products of the novolak and resol type used according to the present invention are reaction products of phenol and its homologues with aliphatic

or aromatic aldehydes.

The usual principles for such product manufacturing are often described in technical literature. Thus -phenol/aldehyde novolacs are usually produced by condensation of phenols in molar excess with aldehydes in an acidic medium.

The liquid state of such products is, among other things, the result of their incomplete drying, until the content of the base substance is in the range of 80 - 90%. Phenol/formaldehyde condensation products of the novo-la-k type are known as commercial mixtures of compounds with the general formula:

where Ar equals oxyphenyl,

n equals 0-10,

The CH^ links are in the 0- and/or p-position with respect to the phenolic hydroxyl. They also contain a certain amount of free phenol and formaldehyde.

Thus, di- and polynuclear compounds such as dioxydiphenylmethane are analogous to phenol/formaldehyde resins of the novolak type.

The most used method for the preparation of resols is carrying out the process under conditions of alkaline catalysis using an excess amount of aldehyde reagent.

Phenol/aldehyde condensation products of the resol type contain a polydispersed mixture of methylol derivatives of

these compounds.with methylol groups placed in ortho- and/or para-positions, with respect to the phenolic hydroxyl, as well as isomeric phenolic alcohols with a phenyl radical (o,p - hydroxybenzylalkhols/ 2,4- and 2,6-dimethylphenols, 2 ,4,6-trimethylphenols).

These compounds are usually considered individual analogs of resol-type phenol/formaldehyde resins.

In the present invention, the above-mentioned components of the phenol/aldehyde condensation products of the resol and novolak type can also be used both in the form of mixtures and as individual analogues. Thus, the expanding preparations as riovolak component can contain any of the three isomeric dioxydiphenylalkanes, e.g. p-p'-dioxydiphenylmethane,

provided that these are sulfonated.- In exactly the same ways, resol in the mixture can be -replaced by 2,4.,.6-trimethylolphenols, 2,2,6,

6'-tetramethylol-4,4'-dioxydif enylacanes. etc.

The many and different methods of production - of the individual compounds ^ of the above-mentioned origin are not the subject of the present invention - Condensation products of the novolak type with a sulfo group in the core are used according to the present invention as novolak resins, these can be produced e.g. by sulfonation of dehydrated novolak resins with any known sulfonating agent (sulfuric acid, sulfuric anhydride, etc.), used in an amount not exceeding one mole per moles of free and bound phenol of the novolak resin.

In addition to the condensation products of the resol type or instead of them, according to the invention, the composition of the mixture that is foamed can include aldehydes which, in the production of plastic foam, play the role of crosslinking agents for the condensation products of the novolak type in an acidic medium. Formaldehyde, acetaldehyde, benzaldehyde and the like can be used here, but preferably formaldehyde is used in the form of aqueous solutions.

The chemical nature of the phenols and aldehydes used for the production of the phenol/aldehyde condensation products of the novolak and resol type has no fundamental significance in connection with the essence of the present invention.

It is e.g. obtained satisfactory results using, apart from phenol itself, isomeric cresols, xylenol and other phenols with at least two unsubstituted ortho and para positions in the nucleus in connection with the phenol hydroxyl, and among

compounds of the aldehyde/formaldehyde type, the low molecular weight polymeric modifications of acetaldehyde and benzaldehyde, etc.

It is preferred to use phenol and formaldehyde, mainly because of the low price and easy availability.

According to the present invention, the sulfono-novolac and the resol components are incorporated into the composition in the mixture in a ratio of 85:15 to 15:85 (calculated on dry weight).

In another embodiment of the present invention, sulfonovolac and aldehyde come together so that the weight ratio is from 95:5 to 60:40. .. r • Expansion and hardening of the foam by the aforementioned procedure is carried out Inhibits acid catalysis. Usually, the functions of the acid catalyst are completely fulfilled by phenol/ the aldehyde condensation products with a sulfo group in the core.

If necessary, it can. in addition to these products with a

sulfo group in the core, other acidic substances are added to the mixture. These substances that are added to the composition to be foamed ensure a pH value in the medium of less than 4.

The acidulant can be as follows:

- mineral acids (hydrochloric acid, sulfuric acid, orthoboric acid, ortho-phosphoric

acid, hydrofluorosilicic acid, etc.),

- organic mineral acids (complex acids based on boric acid-

esters and oxyacids, such as oxalic acid, arylsulphuric acid, etc.),

- anhydrides" and salts of mineral acids. (B2O3/ P2°5' aluminium, calcium, iron chlorides, etc.).

Any of the above-mentioned compounds can be used separately or in admixture with each other.

- As arylsulfonic acids, which can be co-used in form

of reaction products with N-containing compounds and/or aldehydes can be used, pure products, e.g. naphthol-, anthra-

sen-, phenol, benzene, toluene and naphthalene sulfonic acid and commercial products after sulfonation of corresponding aromatic compounds > with known sulfonating agents.

.The foaming of the mixtures based on core sulfo-

nerted novolak-type phenol/aldehyde condensation products or their individual analogues with resol-type condensation products or their individual analogues or with aldehyde

where under acid catalysis, can be carried out using any low-boiling liquid such as lower aliphatic alcohols, aliphatic

isic esters and ketones, saturated aliphatic hydrocarbons, fluoro-chlorohydrocarbons (Freons), halogenated hydrocarbons, gasolines, etc.

According to the present invention, it is for this purpose preferable to use a petroleum ether fraction with a boiling range of from 35 - 50°C at 760 mm Hg..: - The fine structure - in the foamed plasters with a sufficient content of closed pores is achieved by using of such a petroleum ether fraction and also when using some chlorofluorohydrocarbons, e.g. 1,1,2-trifluoro-2,2,1-trichloroethane.

A low-boiling liquid is added to the mixture in an amount of 0>-5 to 30 percent by weight, preferably from 2 to 10 percent by weight, depending on the desired density of the foamed plastic.

According to the present invention, the core sulfonated phenol/aldehyde condensation products of the novolak type or their individual analogues are mixed with saturated hydrocarbons and/or with fluorochlorocarbons (Freons) with a boiling point of from -10°C to -t;800C, where such -combined products simultaneously act as a curing agent and a foaming agent during foam production. Such combined products are sufficiently stable on storage and confirm their effectiveness when mixed with resol-type phenol/aldehyde condensation products and/or aldehydes. ---

Organic substances, with pka below 8 and containing at least one amino, amido, cyanamide or nitrile group, are able to form phenolic compounds and/or absorb formaldehyde in order to reduce the toxic effects of foamed plaster and improve the sanitary conditions during this manufacture. The aforementioned compounds are added to the mixture in an amount of 0.5 - 50, preferably 1 - 20 percent by weight. These compounds are melamine, urea, acrylonitrile, dicyandiamide, m-phenylenediamine, aniline, thiourea and some others.

Most of the aforementioned organic nitro compounds are solid at room temperature and do not mix well with the other components in the foaming mixture. It's fun-

net that these compounds must be added to the mixture in the form of a solution, emulsion or dispersion in water or in suitable organic solvents, e.g. alcohols. However, it is more preferable to add such compounds in the form of their derivatives such as: - complex salts with mineral or aryl sulfonic acids, - resins, including condensation products of urea, melamine dicyandiamide, etc. with formaldehyde in an alkaline or acidic medium.

Hydrochloric urea, urea salts with aryl sulfonic acids,

urea and melamine formaldehyde resins and also cocondensation

products of formaldehyde, arylsulfonic acids and organic compounds containing at least one amino, amido, cyanamide or

nitrile group can; are used as examples of such derivatives.

According to the present invention, the cellular structure of the foamed plasters can be improved and the density can be lowered if surfactants are added to the foaming mixture. - The best results are obtained by using non-ionic surfactants which are added to the composition in an amount of from 0.1 to 10% by weight, preferably 1-3% by weight.

Among the suitable surfactant compounds are the following: silicone oils, polymerization products of ethylene oxide with alkylphenols or higher fatty acids, cellulose ethers such as methyl cellulose, carboTcsymethylcellulose, oxyethylated castor oil, etc.

A partial heat loss in the foaming mixture occurs

when high-boiling liquids are used as foaming agents

due to their evaporation.

"The thermal balance of the process can be improved by

adding to the mixture compounds which release heat as a result of their chemical reaction with water or acid constituents of the foam mixture at temperatures of from 20°C + 10°C.

The best results were obtained by adding to the mixture compounds selected from the following classes: r- carbonates, bicarbonates and alkali and alkaline earth metal nitrites as well as ammonium carbonate, metal hydrides and metal carbides from the second and third group in the periodic table,

- powdered metals standing above hydrogen

in that electromotive voltage series,

- acid anhydrides of the type B2°3°^ P2°5' chloroalkylsilanes (trichloromethylsilane, etc.).

The mentioned substances are added to the mixture in quantities

of 0.1 - 20% by weight, preferably 0.5 - 10% by weight.

The most preferred have been found to be finely dispersed (no more than 200 mesh) powdered metals that stand above hydrogen in the electromotive voltage range, e.g. iron, aluminium, magnesium, cadmium and zinc powders, and especially aluminum and magnesium powders or their mixtures.

The technology for obtaining foam from the phenol/aldehyde condensation products lies in the mixture of special weight ratios - of the aforementioned components with "then the following dosage ay„ the formed ilytende Jolanding" to, the ronv. to be filled with the foam. --"

The mixing of the components and the dosing of the mixture can be carried out in an apparatus which in construction is similar to those used in the production of polyether urethane foam.

Foaming and hardening of the mixture takes place over a period of a few minutes, at temperatures close to room temperature or by heating the mixture and/or the mold to no more than 100°C.

The compositions of the foaming mixtures according to the present invention are. listed below.

In practice, foam according to the present invention is obtained with two or three components in the mixture instead of the six or seven shown in the table, as some of the components listed there can be mixed together so that they form storage-stable products, and they can therefore be mixed in the factory still at the fabrication stage.

The phenol/aldehyde foams according to the present invention have physicomechanical and thermophysical properties similar to those of the known substances of an analogous type, but also have improved flame resistance and flexibility compared to these latter.

The following examples will be of help to those skilled in the art in understanding the details and modifications of the present invention. These examples only serve as illustrations without intending to encompass all the possible aspects of the present invention which emerge from the description given above.

Below is a description of the manufacture of foam mixture components, and the meaning of some trade names for the products used is given.

A. Production of condensation products of the novolak type.

Product I

Production of novolak resins N 1 and N 3

1 mol of phenol is condensed with 0.9 mol of formaldehyde, used as a 37% by weight aqueous solution. The catalyst is sulfuric acid. After the synthesis is finished, the obtained resin is separated from some of the water (resin 1) or from all the water

et (resin 3).

Resin N 1 has an eru ..v in shoe si tet of 5,600 cp at 20°C. and contains 11% water and 10% free phenol..

Resin N 3 _has a droplet drop temperature of 1Q9°C and contains 6% phenol. in the "absence of water...

Product II

Production of liquid novolak resin "",

1 mol of phenol is condensed with 0.7 mol of formaldehyde i

presence of zinc acetate as a catalyst.'

When 90% of the formaldehyde used has reacted, sulfuric acid is added in an amount sufficient to produce a pH in the medium of 1.4, and the condensation is carried out at 100°C for 2 hours. The resin obtained is separated from the water. This resin has a viscosity of 4,200 cp and contains 12% phenol and 13% water.

Product III

Production of sulfonovolac resins N 1, N 2 and N 3

The dewatered novolak resin obtained by

condensation of 1 mol of phenol with 0.65 mol of formaldehyde is sulfonated.

The sulphonation is carried out with 96% sulfuric acid at 90 - 120°C for 4 hours. The sulfone resin obtained is diluted with 25% by weight of water.

The various analysis data are given in the table.

The sulfonated isomeric mixture of dioxydiphenyl methanes is obtained by the same production method.

B. Production of condensation products of the resol type Product IV

Liquid resol resins

The resol resins N 1 and N 2 are produced by condensation of -1 mol of phenol with 1.5 and 2.5 mol of formaldehyde, respectively, at a pH of 8.9 (NaOH as catalyst), a synthesis temperature of 75°C, a reaction time in 1.5 hours with subsequent neutralization of the resins to a pH of 7 - 0.1 and dehydration in vacuum to 82% dry matter residue.

Product V

Trimethylolphenol

Trimethylolphenol is produced by condensation of

1 mol of phenol with 3 mol of formaldehyde in a strongly alkaline medium.

The aqueous solution of trimethylolphenol is dried in vacuo. The various analytical data for trimethylolphenol obtained in this way are as follows:

1) dry matter milled «= 85 %

2) Hoppler viscosity = 5600 cp

3) - Pritted phenol content = 1.2%

C. Manufacturing of combined products

Product VI

Combined products

Compounds containing sulfo groups in the core are treated with petroleum ether or "Freon - 113" at temperatures not exceeding 40°C.

This treatment results in storage-stable products with a white colour.

5 percent by weight of a low-boiling liquid can be introduced into the sulfonated resins while the cocondensation product of sulfophenol, urea and formaldehyde is easily mixed with 20 percent by weight of a low-boiling liquid to form stable products. The polymerization products of ethylene oxide on alkylphenols ("OP - 4", "OP - 7" and "OP - 10") can be used to regulate the size,, of the cells -in the foam plastic that is -manufactured... The foaming agent that was ben< surface was 1,1,2-trichloro-2,2,1-trifluoroethane ("Ereon -

..113") and fluorotrichloromethane ("Freon - 11").-

For the sake of simplicity, examples 1 - 18 which show the production of a phenol/aldehyde foam plastic according to the present invention are summarized in tables 1 - 3.

In all cases, the foam plastic was produced by

mix together the mixture components as indicated in the tables.

The obtained mixture is foamed and shaped without external heat input or in an oven at the pre-selected temperature.

Foaming and curing time take a few minutes, and

does not exceed 30 minutes in any of the examples.

The initial temperature of the mixture is the same i

all the examples and is about 2-CrC-

The time from the mixing of all the mixture components to the beginning of the foaming is referred to as the "foaming induction period".

The obtained foams are tested for strength properties, density, acid value in an aqueous foam extract (acids are extracted from 1 g of foam with 100 ml of water at 20°C for 8 hours), and the flame resistance is also determined.

Examples 1-6 (table 1) show the possibility

to process the mixture into foam, the mixture comprising various phenol/aldehyde condensation products, various acidulants, foam regulators, foaming agents, nitrogen-containing organic compounds and special additives.

In examples 7 - 12 -table 2) the possibility of processing into foam the sulfonated phenol/aldehyde condensation products of the novolak type or their individual analogues is shown. It has also been shown that the mixture can include various products of the resol type, aldehyde and special additives for foaming.

It is worth emphasizing the high bending strength.

These properties exceed the similar properties for known products of an analogue nature by 2-3 times.

Examples -13 - 18 (Table 3) show the possibility of using different weight ratios between aldehyde and core sulfonated phenol/aldehyde condensation products of the novolak type. It is typical for the foam that it does not crumble when exposed to flame in a gas burner for .-5 minutes, while the known substances without flame retardant additives crumble within a few minutes after they are withdrawn from the flame.

Examples 19 - 20 illustrate the use of an atomization technique where two components are added to each atomizer gun.

Example 19

Component I is a mixture of 100 parts by weight resol resin No. 1, 2 parts by weight "OP-7" and 15 parts by weight petroleum ether.

Component II is a mixture of 100 parts by weight of sulpho-novolac resin No. 2 and 3 parts by weight of 76% H-^PC^.

Components I and II are dosed in a weight ratio of 1:1.27.

The components are stirred and sprayed from the spray gun using compressed air under a pressure of 6 atmospheres. The mixture is again foamed for 3 seconds after application to a primary coated metal surface and forms a foam plastic layer with a volume weight of 60 kg/m 3 , and a bending strength of 5.8 kg/cm 2.

Example 20

Component I is a mixture of 100 parts by weight resolhar-pix 1 with 1 part by weight aluminum powder ("PAK-3") and 2 parts by weight

Component II is a mixture of 100 parts by weight of sulfonol varnish resin No. 3 and 4 parts by weight of 70% H-^PO^.

Components I and II are dosed in a weight ratio of 1:0.8 and sprayed under an air pressure of up to 8 atmospheres against a wooden board attached to the ceiling. The mixture foams and solidifies, forming a foam plastic with a volumetric weight of 71 kg/ m 3.

Claims (3)

1. Method for the production of foam plastic with reduced brittleness and improved strength properties by mixing phenol/aldehyde resols and/or aldehydes with phenol/aldehyde novolacs and possibly N-containing additives, foaming and hardening of the mixture by acid catalysis, characterized by mixing core sulphonated phenol/aldehyde- novolaks, the weight ratio between the core sulphonated novolaks and the resplines being 85:15 to 15:85, calculated on a dry basis, while the weight ratio between core sulphonated novolak and aldehyde is 95:5 to 60:40, calculated - on a dry basis. 2. Method according to claim 1, characterized in that urea, melamine, dicyandiamide, acrylonitrile, aniline, thiourea or m-phenylenediamine is added as an N-containing compound in an amount of 1-20% of the total weight of the mixture. 3. Process according to claims log 2, characterized in that urea, melamine, dicyandiamide, acrylonitrile, aniline, thiourea or m-phenylenediamine are mixed in as N-containing compounds in the form of reaction products with arylsulfonic acids and/or aldehydes.