DE19541013A1 - Process for the production of flexible polyurethane foams - Google Patents

Description

The invention relates to a method for producing Flexible foams based on di- and polyisocyanates, especially polyurethane foams, as well as suitable ones Propellant

A well-known chemical blowing agent for PUR soft Foam is carbon dioxide that is used in the manufacture of the Polyurethanes from di- and polyisocyanates and compounds with reactive hydrogen is generated in the presence of water.

It is also known, so-called physical Use blowing agents, namely volatile organic Substances, e.g. B. from the group of ketones, for. B. acetone, the acetates, e.g. B. methyl acetate, ethyl acetate, the halogenhal term alkanes, e.g. B. trichlorofluoromethane (R11), chlorodifluor methane (R22), dichlorofluoroethane (R141b), and halogenated Ether (e.g. E245). The physical blowing agents for poly Urethane foams have to meet certain requirements will. So the blowing agent in the resulting polyurethane insoluble but miscible with the raw materials. It should continue to be thermally stable and non-flammable. From these Fluorinated chlorinated hydrocarbons (CFCs) became common fig used as a physical blowing agent. From ecological For technical reasons, however, their application can no longer be avoided to step.

The object of the invention is a new Ver drive for the production of flexible foams available to provide, which the previous disadvantages of the state of the Technology overcomes.

It was found that 1,1,1,2-tetrafluoroethane in the same way like CFCs for foaming Base of di- and polyisocyanates is suitable; its gerin The solubility in the raw materials is increased by adding Lö Improved intermediaries.

The invention therefore relates to a method for Production of PUR flexible foams using a Blowing agent composition, the 1,1,1,2-tetrafluoroethane (R134a) and at least one further blowing agent component of the group comprising 1,1-difluoroethane (R152a) and organic Compounds with a boiling point <105 ° C, preferably <80 ° C contains. Blowing agents together are also suitable for this the 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane and at least one further organic compound with a Boiling point <105 ° C, preferably contained <80 ° C.

The organic compound is e.g. B. a known physi Kalische propellant. The boiling point is particularly preferred point below 70 ° C.

1,1-difluoroethane or the organic compound fungie ren as a mediator.

Soft foams are foams that are used in Druckbela stung have a relatively low resistance to deformation. The term “flexible foams” preferably denotes in the frame men of the present invention such foams whose Compression stress at 10% compression according to the German indu  standard DIN 53421 is less than or equal to 15 kPa. "PURE" means "polyurethane".

Both binary and propellants can be used together solutions that contain more than two components.

Binary propellant compositions are preferred used. Binary mixtures of are very suitable 1,1,1,2-tetrafluoroethane and 1,1-difluoroethane.

In a preferred variant, the blowing agent contains composition 1,1,1,2-tetrafluoroethane in an amount of 50 up to 95 parts by weight and 5 to 50 parts by weight of 1,1-difluoroethane, in particular 84 to 88 parts by weight of 1,1,1,2-tetrafluoroethane and 12 to 16 parts by weight of 1,1-difluoroethane.

Blowing agents are particularly preferably used from the two components mentioned in the specified menu conditions exist.

A from 84 to 88 wt .-% 1,1,1,2-tetrafluoroethane and from 12 to 16 wt .-% 1,1-difluoroethane existing blowing agent Mix is new and also the subject of the invention.

Another variant of the invention relates to the manufacture development of PUR flexible foams using binary Propellant compositions, the 1,1,1,2-tetrafluoroethane and known liquid physical blowing agents, namely volatile organic compounds with a boiling point <80 ° C contains. They are preferably selected from the Group of ketones, acetates, e.g. B. acetic acid or Ethyl ester, aliphatic acyclic and cyclic Koh hydrogen, halogenated hydrocarbons, ethers, halogen-containing ethers, nitrogen-containing hydrocarbons.  

As a volatile organic compound, the additional Lich used as a blowing agent to 1,1,1,2-tetrafluoroethane a liquid or under pressure is particularly suitable liquefied propellant from the group of ethers with ins a total of 2 to 4 carbon atoms, the ketones with 3 to 4 Koh lenstoffatomen, the aliphatic hydrocarbons with 2 up to 12 carbon atoms, the halogen-containing hydrocarbon substances with 1 to 5 carbon atoms or halogen-containing Ether with a total of 2 to 6 hydrocarbon atoms.

Examples of aliphatic acyclic hydrocarbons are those with 5 to 7 carbon atoms, preferably pentane, hexane, Heptane, as well as gasoline fractions, especially light petrol a boiling point in the range of 15 to 80 ° C. examples for Cyclic hydrocarbons are cyclopropane, cyclopentane and cyclohexane. Among halogenated hydrocarbons become hydrogen-containing chlorofluorocarbons or fluorocarbons or perfluoro compounds e.g. B. Perfluoroalkanes understood. As chlorofluorocarbons are z. B. Chlorodifluoromethane (R22), 1,1-dichloro-1-fluoroethane (R141b), 1-chloro-1,1-difluoroethane (R142b) or 1,3-dichloro- 1,1,2,3,3, -hexafluoropropane (R216a) can be used. examples for Fluorocarbons are pentafluoroethane (R125), 1,1,1- Trifluoroethane (R143a), 1,1,2-trifluoroethane (R143), 1,1-di fluoroethane (R152a), 1,1,1,2,2-pentafluoropropane (R245fa), Octafluoropropane (R218) or 1,1,1,2,2-pentafluorobutane (R365 mfc). Halogen-containing ethers become hydrogen containing fluorochlorine or fluoroethers, such as. B. Difluor methoxy-2,2,2-trifluoroethane (E245) understood. examples for usable ethers are dimethyl ether or diethyl ether. Out The group of ketones is preferably acetone.

The preferred nitrogenous hydrocarbon is nitrome than.  

In a preferred embodiment, one is used Propellant composition containing 50 to 95 parts by weight 1,1,1,2- Tetrafluoroethane and 5 to 50 parts by weight of at least one of the contains the aforementioned physical blowing agents. Bi nary compositions consist of the components mentioned in the specified composition. Very suitable together Solutions contain 50 to 95 parts by weight of 1,1,1,2-tetra fluoroethane and 5 to 50 parts by weight of 1,1-difluoroethane, 1,1,1,2,2-pentafluorobutane, 1,1,1,3,3-pentafluorobutane or Difluoromethoxy-2,2,2-trifluoroethane, or consist of such mixtures.

Also blowing agent compositions, the 1,1,1,2-tetra fluoroethane and at least two other physical propellants contain medium, can be used. 1,1,1,2-tetrafluoroethane is contained with 50 to 95 parts by weight, the other blowing medium with a total of 5 to 50 parts by weight. Well suited are blowing agent compositions that are 50 to 95 parts by weight Contain 1,1,1,2-tetrafluoroethane and a total of 5 to 50 parts by weight of a mixture of 1,1-difluoroethane and min at least one other physical blowing agent, the Weight ratio of 1,1-difluoroethane to the other physika mical blowing agent is 1:10 to 10: 1. Such last Mixtures mentioned, consisting of R134a, R152a and another physical blowing agents exist, are new and also Subject of the invention.

In the composition according to the invention, in addition to the actual propellants, other conventional ones Excipients such as B. flame retardants, emulsifiers, foam Stabilizers, binders, etc. may be included.

The inventive method can übli in the presence cher flame retardant carried out in the reaction mixture will. These include, for example, reactive flame retardants  medium and especially flame retardants based on organi phosphorus compounds. Phosphate is very suitable esters and phosphonic esters, the organic groups, too can be substituted by one or more halogen atoms, exhibit. The organic groups can be aliphatic or have aromatic character. Are very suitable Phosphate esters and phosphonate esters by three C₁-C₆-Al alkyl groups, which may have one or two halogen atoms, are substituted, for example trischloroisopropyl phosphate, Trischloroethyl phosphate, trischloropropyl phosphate, dimethyl ethyl phosphate, tris dichloroisopropyl phosphate, dimethyl methyl phosphonate, preferably tris chloropropyl phosphate. As a stabilizer Examples of copolymers made from siloxane are suitable for use in the case of isolators net.

The use of the new one is also particularly suitable Blowing agent for the production of flexible foams based of di- or polyisocyanates.

Will the inventive method for manufacturing soft foamed PUR plastics are used here with all common foam raw materials such as B. aliphatic, cycloaliphatic or aromatic di- or polyisocyanates be used. Examples of foam raw materials are e.g. B. 2,4- and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, Polymethylene polyphenyl isocyanate and mixtures thereof. It can also carbodiimide groups, urethane groups, allophanate groups pen, isocyanurate groups, urea groups or biuret groups contained polyisocyanates, which are called modified polyiso Designated cyanates or isocyanate prepolymers, who used the. In the production of soft foamed PUR plastic Polyisocyanates are usually treated with compounds set that reak at least two towards isocyanate groups contain capable hydrogen atoms, for example Hy Compounds containing hydroxyl groups on polyester, poly  ether and amine base, as well as amino and / or carboxyl and / or compounds having tiol groups. Can continue all in the production of foamed PUR plastics catalysts used such. B. tertiary amines and / or organic metal compounds such as tin salts of carboxylic acids are used. Are also suitable organic amines, amino alcohols or amino ethers, e.g. B. 2-Tue methylaminoethyl-3-dimethylaminopropyl ether, diethanolamine, Dimethylcyclohexylamine, 2-dimethylaminoethyl ether, or Mor pholine compounds such as B. 2,2-dimorpholinodiethyl ether, N, N-dimethylaminoethylmorpholine, N-methylmorpholine. Prefers are the morpholine compounds, especially 2,2-dimorpholi nodiethyl ether.

In a manner known per se, in addition to the polymers and / or polymerizable constituents all known additives or auxiliaries, for example Nucleating agents, pore regulator substances, flame retardants, Antistatic agents, stabilizers, plasticizers, crosslinking agents, Fillers or dyes can be added.

As a polyol component such. B. glycerol, glycols or Polyether polyols used as addition products of propylene oxide or ethylene oxide to polyhydric alcohols, water or ethyl lendiamine were obtained, or polyester polyols, which as Polycondensation products from polyols with dicarboxylic acids or their anhydrides have been obtained, or mixtures thereof ben contained in the PUR foam mixture. A typical one Polyol component can e.g. B. a mixture of a polyether polyol (e.g. diol or triol) with a hydroxyl number from 15 to 330 and higher and a polyether polyol (e.g. a diol) with a hydroxyl number of 32. Wei also modified vegetable oils with an OH number in the range of about 20 to about 180, e.g. B. castor oil possible.  

As a di- or polyisocyanate component z. B. Diphe nylmethane-4,4'-diisocyanate, tolylene diisocyanate, diisocyanate to-toluene, 1,5-diisocyanato-naphthalene, triisocyanato-triphe nylmethane, 1,6-diisocyanatohexane, preferably diphenylme than-4,4'-diisocyanate, or mixtures thereof, who used the.

A typical PUR foam mixture that is beneficial using the blowing agent composition according to the invention lets foam, for example consists of about 53 wt .-% a polyol component, e.g. B. from a mixture of a poly ether polyols with a hydroxyl number of 32 to 48 and one Polyether polyol with a hydroxyl number of 56 in the mixture ratio 2: 1, approx. 36% by weight of a polyisocyanate component, e.g. B. tolylene diisocyanate, about 0.15 wt .-% of a catalyst substance such as B. triethylenediamine, about 1.0 wt .-% silicone foam stabilizer, approx.2.4% by weight water, approx.4.0% by weight a flame retardant, e.g. B. trichloropropyl phosphate, about 3.7% by weight of the blowing agent mixture according to the invention.

With the blowing agent composition according to the invention In particular, PUR flexible foams with bulk densities can be used below 20 kg / m³ especially in the range from 14 to 18 kg / m³ produce. This density range is only available at Ver use of trichlorofluoromethane (R11) or other known Blowing agents can be achieved. The foams also stand out fabrics through increased flexibility, the so-called Supersoft behavior. Furthermore, the danger of scor ching greatly reduced. Among scorching is the inclination of the Foam to discolour due to increased temperature understanding during the development. Fabrics for tend to discolor, e.g. B. for certain applications not suitable. This discoloration effect often occurs in the Production of foams with a bulk density below 20 kg / m³ when water was used as a blowing agent.  

The following examples are intended to illustrate the invention explain, but without limiting their scope.

Examples Example 1 (comparative example)

To produce the PUR flexible foam, a Mi from

70 parts by weight of polyether polyol OHZ 36
30 parts by weight of polyether polyol OHZ 95
5.3 parts by weight of water
0.12 part by weight of triethylenediamine, as a 33% solution in dipropylene glycol (thancate)
0.1 part by weight of tin octoate
1.9 parts by weight of BF 2370 foam stabilizer from TH Goldtschmidt
65.5 parts by weight of tolylene diisocyanate with an isomer mixture of the 2.2 or 2.6 tolylene diisocyanate compound from 80% to 20% (TDI 80)

with 12 parts by weight of trifluoromethane (R11) as blowing agent foams.

Example 2 (comparative example)

The same starting mixture as in Example 1 was used 10.5 parts by weight of 1,1-dichloro-1-fluoroethane (R141b) as a blowing agent medium foamed.

Example 3

The starting mixture analogous to Example 1 was 8.5 wt. Share a mixture of 1,1,1,2-tetrafluoroethane (R134a) and 1,1-difluoroethane (R152a) in a ratio of 86:14 (by weight) as Foaming agent foamed.  

The results are shown in Table 1.

Table 1

Claims (6)

1. A process for the preparation of flexible foams based on di- or polyisocyanates by reacting di- or polyisocyanates with compounds having at least two hydrogen atoms which are reactive toward isocyanate groups, using a blowing agent and optionally further additives, characterized in that a blowing agent is used is the 1,1,1,2-tetrafluoroethane and at least one other blowing agent component from the group comprising 1,1-difluoro-ethane and volatile organic compounds with a boiling point <105 ° C, preferably <80 ° C from the Group of ketones, acetates, aliphatic and cyclic hydrocarbons, halogenated hydrocarbons or nitrogenous hydrocarbons contains. 2. Process for the production of flexible foams Claim 1, characterized in that a blowing agent is set, the 50 to 95 parts by weight of 1,1,1,2-tetrafluoro ethane and 5 to 50 parts by weight of the other blowing agent compo contains nente or blowing agent components. 3. Process for the production of flexible foams according to claim 1, characterized in that a blowing agent from 50 to 95 parts by weight of 1,1,1,2-tetrafluoroethane and 5 to 50 parts by weight of a mixture of 1,1-difluoroethane and one volatile organic compound with a boiling point <80 ° C is used as additional blowing agent components. 4. The method according to claim 1, characterized in that a blowing agent is used which consists of 84 to 88 wt .-% 1,1,1,2-tetrafluoroethane and 12 to 16% by weight 1,1-difluoroethane consists.   5. Blowing agent composition for carrying out the Ver driving according to one of claims 1, 2 or 3, characterized by a content of 50 to 95 wt .-% 1,1,1,2-tetrafluoro ethane and 5 to 50 wt .-% of another blowing agent components te from 1,1-difluoroethane and a volatile organi rule with a boiling point <105 ° C, preferably <80 ° C, from the group of ketones, acetates, aliphatic acyclic and cyclic hydrocarbons and the stick hydrocarbons containing substances. 6. Blowing agent composition for carrying out the Ver driving according to one of claims 1, 2 or 4, characterized ge indicates that it consists of 84 to 88 wt .-% 1,1,1,2-tetrafluoro ethane and 12 to 16 wt .-% 1,1-difluoroethane.