DE2428307A1 - FOAMED POLYMERS - Google Patents

Description

"Foamed Polymers" The invention relates to manufacture of foamed polymers and, in particular, of the production of solid polyisocyanurate foams.

It is already known to produce solid polyisocyanurate foams by that reaction mixtures are produced, which an organic polyol, an organic Polyisocyanate in an excess amount with respect to the polyol and other effective substances hydrogen-containing materials, a trimerization catalyst and a propellant, possibly including other additives, such as foam stabilizers, contain.

In the process as described in British Patent 1,223,415 is described, the organic polyol used is a polyesterification product with a hydroxyl value within the range of 200 to 700 mg KOH / g and not more than 1.5 branch points per 1000 units of molecular weight and the polyisocyanate is a crude diisocyanatodiaryl alkane composition which Contains from 5 to 70% by weight of polyisocyanates with a functionality greater than 2. Foams made by the process of British Patent 1,223,415 have excellent high temperature properties and excellent Fire resistance properties in general in connection with a low Friability. However, if such foams under certain conditions of exposure exposed to fire, cracks will form and while the foamed polymer is extremely resistant to burning, flames can get through the cracks penetrate to an undesirable extent. It has now been found that this Prevents cracking in such foams and improves fire resistance can be achieved if a stimulant is added to the foam formulation.

The present invention now provides a method of manufacture proposed by solid polyisocyanurate foams, which consists in that a Polyester esterification product having a hydroxyl value within the range of 200 to 700 mg KOH / g and not more than 1.5 branch points per 1000 units of molecular weight, a blowing agent, a catalyst for the trimerization of isocyanates, an expanding agent and a crude diisocyanatodiaryl alkane substance composition are mixed which from 5 to 70% by weight of polyaryl polyalkylene polyisocyanates having a functionality contains more than 2 and this substance composition in such an amount is present that from 3 to 10 equivalents of the isocyanate group åe Equivalents of active hydrogen are present.

Suitable polyesterification products for use in the present Processes are preferably liquid at room temperature and they can be carried out by customary Polyesterification processes are produced. It is usually particularly useful to manufacture the polyesterification products in that one or more polyols are reacted with one or more polycarboxylic acids or their anhydrides, wherein the polyol components are used in an amount sufficient to ensure that the products have hydroxyl values within the range of 200 up to 700 mg KOH / g and low acid values, for example those of less than 10 mg KOH / g and preferably less than 3 mg KOH / g.

close suitable polyols for the production of the polyesterification products a: aliphatic polyols, especially diols, for example ethylene glycol, diethylene glycol and propylene glycol, and suitable polycarboxylic acids are aliphatic dicarboxylic acids, for example adipic acid. In addition to the diols and dicarboxylic acids, polyols can be used higher functionality, for example glycerol, trimethylolethane, trimethylolpropane and pentaerythritol, or acids of higher functionality of the polyesterification mixture be incorporated in quantities by up to 1.5 branch points per 1000 units the molecular weight.

The polyesterification products can be at the lower end of the hydroxyl value range Be polyester, which has an average molecular weight of up to. to own 1000. At the higher end of the hydroxyl range, the polyesterification products consist primarily from blends of low molecular weight polyesters such as diesters with different amounts of non-esterified polyol.

The polyesterification products can thereby be particularly expedient be prepared that one or more polyols with one or more dicarboxylic acids or the corresponding anhydrides are reacted in such amounts that the Ratio of hydroxyl to carboxyl groups within the range of 5: 1 to 1.25: 1. Suitable materials, which in the method according to the invention can also be made by having appropriate Materials are mixed together, for example by mixing one Polyester with a hydroxyl value of less than 200 mg KOH / g with a material, for example a glycol which has a hydroxyl value of more than 700 mg KOH / g.

The degree of branching of the polyesterification products can be determined from the Proportions and the functionality of the materials are calculated, which are used in the Manufacture of these products are used. A product made from completely bifunctional Materials, contains no branch points, while a polyester, which contains one gram-mole of a combined trihydric alcohol in 1000 g, one Has branch point per 1000 units of the molecular weight and a polyester, which contains one gram-mole of a combined tetravalent alcohol in 1000 g, two Branch points each having 1000 units of molecular weight.

The polyesterification products, which in the inventive method are used, result in foams which have high softening points and high durability versus burning associated with the absence of the occurrence of brittleness exhibit. Polyesterification products, with hydroxyl values less than 200 mg KOH / g result in foams which have a tendency to shrink and worse Have high temperature and flame resistance properties, while those which have hydroxyl values of more than 700 mg SOH / g, result in more brittle foams. Increased brittleness can also be observed in foams made from polyesterification products produced which have more than 1.5 branch points per 1000 units of the Have molecular weight. These latter polyesterification products can be used in certain cases have high viscosities which make them somewhat difficult to obtain to be used in foaming processes. Polyether with hydroxyl values within of the range from 200 to 700 mg KOH / g usually give foams with a lower level Fire resistance than the polyesterification products.

In the process according to the invention, small amounts of other Polyols can be used in conjunction with the polyesterification product. Suitable Polyols include monomeric compounds such as ethylene glycol, which is used as a solvent for the trimerization catalyst is needed, as well as polyether, which through Reaction of alkyne oxides with compounds are produced which have several active Contain hydrogen atoms.

The crude diisocyanatodiaryl alkane compositions disclosed in Processes used according to the invention are mainly mixtures of Diisocyanatodiarylalkanes and polyaryl polyalkylene polyisocyanates of one functionality greater than 2 and they are produced by phosgenation of crude diaminodiarylalkanes, which in turn by reacting aromatic amines, such as aniline, Ohloranilinen or Toluidinen or mixtures of such amines with an aldehyde or Ketone. The production of such polyisocyanate compositions, in particular of diisocyanatodiaryl methane compositions which differ from Derive polyamines, the reaction of aromatic amines, especially aniline with formaldehyde, are extensively in the liter for example in British Patent Nos. 687 055 and 848 671.

The crude diisocyanatodiarylalkane compositions which are used in the process according to the invention contain from 5 to 70% by weight of polyaryl polyalkylene polyisocyanates with a functionality of greater than 2, but it is particularly advantageous to use compositions of matter which 20 to 60% rj > contain such polysocyanates. The raw substance compositions can be given by the general formula in which X denotes an alkylene radical and n has an average value from 0.05 to about 1.2.

The crude diisocyanatodiaryl alkane composition is used in a Amount used to be from 3 to 10 and preferably from 4 to 6.7 equivalents of the Isocyanate group to supply per equivalent of active hydrogen in the reaction mixture.

The active hydrogen atoms are in the hydroxyl groups of the polyesterification product and also present in any of the remaining free carboxylic acid groups therein. The active hydrogen atoms can also be present in other components of the foam forming reaction mixture be present, for example as hydroxyl groups in nonionic Surfactants, which in small amounts can be applied. If necessary, water can also be used in small amounts Propellants are used. Foams produced by; that the polyisocyanate fabric composition is used in such an amount as to more than 10 equivalents of isocyanate group per equivalent of active hydrogen have proven to be too brittle for many purposes, while foams, those with less than 3 equivalents of isocyanate group per equivalent of active hydrogen are produced, including poorer high temperature properties of fire resistance.

Particularly suitable propellants for use in the inventive Processes are liquids having a low boiling point, which under evaporate under the influence of the exothermic polymerization reaction.

Suitable, low boiling point. Liquids are those which are inert towards the organic polyisocyanate and the boiling points at atmospheric pressure not exceeding 10,000 and preferably not are above 50 ° C. Examples of such liquids are halogenated hydrocarbons and especially fluorinated hydrocarbons such as trichlorofluoromethane and dichlorodifluoromethane. These liquids are preferably used in amounts of 5 to 40% by weight of the polyisocyanate applied. When the propellant has a boiling point below room temperature foam techniques can be used.

Water acts as a blowing agent and can optionally be used in amounts up to to be used at 2 wt .-% of the polyisocyanate.

It is usually preferred to create foams which contain the have the most satisfactory properties, that the crowd of water should not be greater than 0.1% by weight of the polyisocyanate.

Catalysts that form the trimerization of isocyanates Promote products contain an isocyanate ring structure and are deeply into in the literature, for example in British Patents 809 809, 837 120 and 856 372.

Suitable catalysts include strong bases such as quaternaries Ammonium hydroxides, for example benzyltrinethylamine hydroxide, alkali metal hydroxides, for example potassium hydroxide, and alkali metal alkoxides, for example sodium methoxide. Other suitable catalysts include less basic materials Nature, such as alkali metal salts of carboxylic acids, e.g. sodium acetate, potassium acetate, Potassium 2-ethylhexoate, potassium adipate and sodium benzoate, certain tertiary amines, for example N-alkylethyleneimines, N- (2-dimethylaminoethyl) -N'-methylpiperazine and tris-3-dimethylaminopropylhexahydro s-triazine. Other suitable catalysts include non-basic metal salts of carboxylic acids such as lead octoate. In many cases it is beneficial to in connection with the said catalysts to use materials that per se are not suitable for trimerizing isocyanates to a considerable extent. Such materials include the greatest number of aliphatic tertiary Amines, such as 1,4-diazabicyclo-, 2,27-octane and N, N-dimethylbenzylamine, certain organic metal compounds, for example stannous octoate and dibutyltin dilaurate, and epoxides, for example propylene oxide, phenol glycidyl ether and diglycidyl ether of 2,2-bis-4-hydroxyphenylpropane. Certain tertiary amines, for example 1,4-diazabicyclo-g2,2,27-octane and N, N-dimethylcyclohexylamine act in the presence of epoxides as Catalysts for the trimerization of isocyanates.

Many of these materials, such as tertiary amines and tin compounds are of course generally known as catalysts for the conversion between Isocyanates and hydroxy compounds and accordingly they promote the reaction between Isocyanate groups and the hydroxyl groups of the polyesterification product.

The best amount of catalysts to use depends on a lot to a large extent on the effectiveness of the particular catalyst used. In general it is preferred to use from 0.1 to 5, preferably 0.5 to 3, oC /, of catalysts, based on the weight of the crude diisocyanatodiarylaccane material composition use.

The blowing agent used in the method of the invention is an organic or inorganic solid material that is suitable expand to at least three times its original volume, if it is exposed to a temperature of approximately 150 ° C or above. Examples of such Agents are thermally expanding graphite, as in the US patent 3,574,644, vermiculite and sucrose.

Suitable amounts of the blowing agent are within the range from 2 to 40 wt .-, based on the total amount of the foam-forming ingredients.

In addition to the ingredients already mentioned, the foam-forming Reaction mixture other additives of the types are incorporated as they are general for the production of polymer foams from organic polyisocyanates. For example, the reaction mixture can contain surfactants or foam stabilizers contain, such as siloxane / oxy-alkylene copolymers and ethylene oxide / propylene oxide block mixed polymers, Flame retardants, such as trischloroethyl phosphate and Trischloropropyl phosphate, non-puff fillers and antioxidants.

The foaming ingredients can be made using any of of the methods used for the production of polymer foams from organic Polyisocyanates have been described. So can using a one-step process be worked, with both the polymerization reactions and the foam formation can be done in a single operation. In such a procedure, the entire Polyesterification product and all of the diisocyanatodiarylalkane composition reacted with one another in the presence of the propellant and trimerization catalyst. Otherwise, however, the prepolymer and quasi prepolymer processes can also be used are, at least part of the polyesterification product and at least one Part of the crude diisocyanatodiaryl alkane composition in the form of a prepolymer present which has free isocyanate groups during the foaming treatment.

When a prepolymer process is used, it is preferred that at least from 15 to 80% by weight of the pre-esterification product in the form of a prepolymer are present.

The preparation of the prepolymer can be carried out using the methods described in the literature the conditions described for such working methods must be carried out. So can the polyesterification product and the diisocyanatodiaryl alkane composition are reacted with one another at normal or elevated temperatures, until the implementation is essentially complete. In general, it has been found to be proven to be useful, the desired proportion of polyesterification product with the Total amount of Diisocyanatodiarylalkanstoffzusainmensetzung that causes foam is necessary to implement. The working stage for foam production consists in that the prepolymer with the remaining polyesterification product, which for Foaming is required, and optionally another crude diisocyanatodiarylalkane composition are mixed in the presence of the propellant and the drimserization catalyst, the total ratio of isocyanate groups to active hydrogen atoms within in the range from 3: 1 to 10: 1.

The solid foams produced by the method according to the invention have excellent resistance to deformation at high temperatures and excellent fire resistance.

The fire resistance can be determined by the ASTN D1692-59T-Flame Test, the ASTM E84-61 Tunnel Test, the ES 476 Surface Spread of Plame Test, or the Burn-through Test of the U.S.

Bureau of Mines to be demonstrated.

The products produced according to the invention are particularly suitable for Use as insulation materials and as building and construction elements, in particular if they are exposed to high temperatures and / or the effects of fire. For structural applications, the foams can be in the form of laminates with others Materials such as cardboard, asbestos, plasterboard, steel and paper can be used.

The invention is explained in more detail in the following examples, without to be limited to it. The parts and percentages are based on weight.

Example 1 Expandable graphite flakes are made according to U.S. Patent 3,574,644 column 4, lines 19-26.

A solid foam (A) is made by mixing the following ingredients made: 6.8 parts of a polyester made from 739 parts of diethylene glycol, 201 parts of trimethylolpropane and 695 parts of adipic acid, having a hydroxyl value of 360 mg KOH / g and an acid value below 3 mg KOH / g.

1.3 parts of a polyoxypropylene / oxyethylene block copolymer which contains about 10 ffi ethylene oxide residues and has a molecular weight of about 2000, 0.3 parts of a siloxane / polyoxyalkylene mixed polymer, 3.3 parts of tris (chloropropyl) phosphate, 5.5 parts of trichlorofluoromethane, 1 part of potassium acetate, 1 part of ethylene glycol, 33 parts a diphenylmethane diisocyanate composition containing about 55% diisocyanatodiphenylmethane isomers contains, the remaining mass of isocyanate as polymethylene polyphenyl polyisocyanate is present with a functionality of more than 2 and the NCO content is 29.2%, 16.5 parts of expandable graphite Similar foams were made by (B) omission of graphite and (C) using untreated graphite.

The foams were subjected to a burn-off test using a foam disk 2.54 cm thick placed vertically and the flame of a small Bunzenburner was exposed. The time within which the flame penetrates the pane, was decided.

Foam A burns through in 300 minutes, foam B burns in 33 minutes and Foam C will burn through in 70 minutes.

Example 2 In this example, the graphite is ground in a mill, so that it passes through a mesh screen of 0.5 mm before treatment.

One produced using 16.5 parts of graphite according to Example 1 Foam has a burn through time of 200 minutes. When the graphite content is 33 Parts is increased, the foam will not burn through after 7 hours.

For all foams containing expandable graphite, none was found Cracking detected in the foam when exposed to the flame, while the foam B according to Example 1 has numerous cracks.

Example 3 In this example, powdered vermiculite became superfine Grain size used, which was previously dried to constant weight at gOOC is. Example 1 is repeated, with the expandable graphite replaced by an equivalent Amount of vermiculite was replaced. The foam has a burn-through time of 25 minutes, however, shows no cracking. If the vermiculite is used without prior drying is, then water is released in the foaming stage, so that a material is lesser Density arises, which has a lower resistance to burn-through.

Example 4 In this example the graphite of example 1 is replaced by 16.5 parts of powdered 4-ifitroaniline-2-sulfonic acid ammonium salt. Which resulting foam has a burn through time of 105 minutes.

Example 5 Foams are produced according to Example 1, but with the graphite is replaced by powdered sucrose. The results are as follows Achieved: amount of sucrose burn through time 3.3 parts 75 minutes 8.2 parts 158 minutes 16.5 parts 1.55 minutes.

Example 6 A mixture of the following ingredients is prepared: 53.7 parts of the polyester described in Example 1, 1.92 parts of ethylene glycol, 10.5 parts of the polyoxypropylene / polyoxyethylene diol block copolymer described in Example 1, 0.07 parts of water, 2.1 parts of a siloxane / oxyalkylene mixed polymer, 1.92 parts Potassium acetate.

A second mixture is made from the following ingredients: 263 parts of the diphenylmethane diisocyanate composition as described in Example 1, 79 parts powdered sucrose, 54.2 parts trichlorofluoromethane.

The two mixtures are mixed together and put into a mold poured from two iron sheets of 45.7 x 45.7 cm x 0.91 mm in size, which through are separated from each other by a wooden frame measuring 2.54 x 5.08 cm.

The resulting double-faced iron plate with a foam core 45.7 x 45.7 x 5.08 cm in size was subjected to the following test: The plate is clamped in a position 9 cm from an oven, the temperature of which is regulated in this way becomes that it changes over time according to the following ratio: T-To = 345 lo O (8t + 1). In this formula, t = test duration in minutes, T = oven temperature in ° C at time t, and T0 = initial furnace temperature in 00. The temperature of the The surface of the plate exposed to the oven is measured by three thermocouples. The temperature of the plate surface not exposed to the oven is five Thermocouples measured, one in the center of the plate and one in the center of the plate is in the center of each quarter section. During the trial is the mean of the five thermocouple displays as a measure of the exposure to the oven Surface temperature measured.

During the described examination of the plate, 38 minutes pass, to bring the surface exposed to the oven to a temperature of 140 ° C.

A second panel is made from a formulation that is apart does not contain sucrose of any of the listed ingredients. If this record is the If the same experiment is exposed, 27 1/2 minutes will elapse in order to reach the temperature to increase to 140 ° C.

Example 7 A solid foam is produced from the following components: 4.53 parts of the polyester described in Example 1, 0.87 parts of that in Example 1 described polyoxypropylene / oxyäthylen-Blockmisc hpolymers, 0.2 Parts of a siloxane / polyoxyalkylene mixed polymer, 0.17 part of ethylene glycol, 3.7 Parts trichlorofluoromethane, 0.17 parts potassium acetate, 0.008 parts water, 20.66 parts a diphenylmethane diisocyanate composition comprising about 77 ffi of diisocyanatodiphenylinethane Contains isomers, the remaining mass of isocyanate in the form of polymethylene polyphenyl polyisocanaves with a functionality of greater than 2 is present and the NCO content is 31.4 ffi is 9.4 parts of suadehearable graphite.

When the foam was examined in the manner described in Example 1 it can be determined that it burns through in 110 minutes without cracking, while a similar foam made with no added graphite is inside burns through for 68 minutes with very considerable cracking.

Example 8 A solid foam is made by mixing the following ingredients made: 4.9 parts of a polyester made from 808 parts of diethylene glycol and 390 parts of adipic acid having a hydroxyl value of 500 mg KOH / g and an acid value below 3 mg KOH / g, 1.33 parts of the polyoxypropylene / polyoxyethylene mixed polymer according to Example 1, 0.26 part of siloxane / polyoxyalkylene copolymer, 0.25 part of ethylene glycol, 6.6 parts trichlorofluoromethane, 0.25 part potassium acetate, 0.01 part water, 33.0 Parts of the diphenylmethane diisocyanate composition described in Example 1, 14.8 Share sucrose.

This foam burns through in 132 minutes, while a similar one Foam produced without the addition of sucrose within 70 minutes blows.

Example 9 A solid foam is made by mixing the following ingredients made: 88.2 parts of a polyester made-from 106.3 parts of polypropylene glycol, 48 parts of trimethylolpropane, 53 parts of phthalic anhydride and 130.8 parts of alipic acid with a hydroxyl value of 260 mg KOñ / g and an acid value below 3 mg KOH / g, 12.0 Parts of a polyoxypropylene / oxyethylene block copolymer as described in Example 1, 2.4 parts of a siloxane / polyoxyalkylene mixed polymer, 20 parts of trischloropyl phosphate, 2.25 parts of ethylene glycol, 38.0 parts of trichlorofluoromethane, 2.25 parts of potassium acetate, 0.1 part of water, 300 parts of the diphenylmethane diisocyanate composition Example 1, 138.2 parts sucrose.

This foam burns through in 119 minutes, while a similar foam, which was made without sucrose, burns through in 70 minutes.

Ps tent claims:

Claims (3)

Claims: 1. Process for the production of solid polyisocyanate foams, whereby a reaction mixture is prepared which is a polyesterification product with a hydroxyl value within the range of 200 to 700 mg KOE / g and not - more than 1.5 branch points per 1000 units of molecular weight, a blowing agent, a catalyst for the trimerization of isocyanates; and a crude diisocyanatodiaryRalkane material composition Contains from 5 to 70 wt .-% polyaryl polyalkylene polyisocyanate with a functionality of more than 2, said fabric composition in such an amount it is present that 3 to 10 equivalents of isocyanate group per equivalent of active hydrogen are delivered, characterized in that the reaction mixture also has a Contains bloating agents. 2. The method according to claim 1, characterized in that the raw Diisocyanatodiaryl alkane composition is used in an amount that supplied from 4 to 5.7 equivalents of isocyanate group per equivalent of active hydrogen will. 3. The method according to claim 1 or 2, characterized in that the amount of blowing agent is within the range of 2 to 40% by weight to the total amount of foam-forming components.