DE19822944A1 - Production of polyurethane foam with improved properties, especially low thermal conductivity at low temperature - Google Patents

Abstract

A blowing agent for the production of polyurethane (PU) foam with improved properties contains (a) pentafluoropropane and/or pentafluorobutane and (b) at least one other component selected from optionally halogenated low-boiling hydrocarbons, ethers or halo-ethers and other fluoro-hydrocarbons. A process for the production of PU foam in which the blowing agent comprises a mixture containing (a) pentafluoropropane (preferably 1,1,1,3,3-pentafluoropropane (HFC-245fa)) and/or pentafluorobutane (preferably 1,1,1,3,3-pentafluorobutane (HFC-365mfc)) and (b) at least one other component selected from optionally halogen-substituted low-boiling hydrocarbons, ethers and halogenated ethers, difluoromethane (HFC-32), difluoroethane (preferably 1,1-difluoroethane (HFC-152a)), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoropropane (preferably 1,1,1,3,3-pentafluoropropane (HFC-245fa)), hexafluoropropane (preferably 1,1,2,3,3,3- or 1,1,1,3,3,3-hexafluoropropane (HFC-236ea and HFC-236fa)) and heptafluoropropane (preferably 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea)). Independent claims are also included for (a) mainly closed-cell PU foam containing the above blowing agent compositions; (b) a blowing agent mixture for the production of PU foam with improved properties with regard to thermal conductivity at low temperature, containing or comprising from 1 - 50 wt% HFC-365mfc and from more than 50 to 99 wt% fluorocarbon(s) selected from HFC-134a, HFC-245fa, HFC-236fa and HFC-227ea.

Description

The invention relates to a method for manufacturing position of polyurethane foams.

Polyurethane foams are used as heat and noise insulating building materials. The production of single and multi-component polyurethane foams with blowing agents based on liquefied CO ₂ is disclosed in WO 96/14354.

The object of the present invention is a method for the production of polyurethane foams by means of a selected, novel, advantageous propellant ben. This task is accomplished through the process and the drive solved by the present invention.

The starting point was the surprising finding that Pen tafluoropropane, especially pentafluoropropane (HFC-245fa) or Pentafluorobutane, especially 1,1,1,3,3-pentafluorobutane (HFC- 365mfc) mixed with certain other blowing agents very good for the production of polyurethane foams provides a suitable composition.

The inventive method for the production of Po lyurethane foams with the help of a blowing agent before using a composition as a blowing agent the a) pentafluoropropane, preferably 1,1,1,3,3-pentafluor propane (HFC-245fa) and / or pentafluorobutane, preferably 1,1,1,3,3-pentafluorobutane (HFC-365mfc) and b) at least one  further blowing agent selected from the group comprising low-boiling, optionally halogenated hydrocarbons substances, ethers and halogen ethers; Difluoromethane (HFC-32); Tue fluoroethane, preferably 1,1-difluoroethane (HFC-152a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1,2-tetrafluoroethane (HFC-134a); Pentafluoropropane, preferably 1,1,1,3,3-penta fluoropropane (HFC-245fa); Hexafluoropropane, preferably 1,1,2,3,3,3-hexafluoropropane (HFC-236ea) or 1,1,1,3,3,3- Hexafluoropropane (HFC-236fa); and heptafluoropropane, preferred as 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) contains or consists of it.

If you use a pentafluoropropane, you use preferably HFC-245fa. If you use a pentafluorobutane, HFC-365mfc is preferred. This is the following explained in more detail.

In one embodiment, a propellant is used tel which is 1,1,1,3,3-pentafluorobutane, 1,1,1,3,3-pentafluoro propane and at least one of the propellants mentioned under b) medium.

According to another embodiment, a blowing agent is used which has 1,1,1,3,3-pentafluoropropane and at least one further blowing agent different from 1,1,1,3,3-pentafluoropropane mentioned under b) (the Use of pure pentafluoropropane is not part of the invention). A useful mixture is e.g. B. HFC-245fa and HFC-152a and / or HFC-32, optionally with the addition of liquefied CO ₂ .

Preferred is the embodiment which 1,1,1,3,3- Pentafluorobutane as component mentioned under a).  

The method according to the invention preferably provides that a composition is used as the blowing agent which 1,1,1,3,3-pentafluorobutane (HFC-365mfc) and at least one further blowing agent selected from the group comprising low-boiling, optionally halogenated hydrocarbons substances, ethers and halogen ethers; Difluoromethane (HFC-32); Tue fluoroethane, preferably 1,1-difluoroethane (HFC-152a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1,2-tetrafluoroethane (HFC-134a); Pentafluoropropane, preferably 1,1,1,3,3-penta fluoropropane (HFC-245fa); Hexafluoropropane, preferably 1,1,2,3,3,3-hexafluoropropane (HFC-236ea) or 1,1,1,3,3,3- Hexafluoropropane (HFC-236fa); and heptafluoropropane, preferred as 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) contains or consists of it.

The term "low-boiling, optionally halogenated hydrocarbons, ethers and halogen ethers" means compounds with a boiling point below 70 ° C. Suitable hydrocarbons are e.g. B. ethane, propane, butane, pentane and hexane and mixtures thereof. Isomerically pure compounds or mixtures of different isomers can be used. “Butane” means mixtures of n-butane and i-butane. Such mixtures are commercially available. Rei nes n-butane or i-butane or their mixture in any composition can also be used, but is very expensive. The same applies to higher homologs such as pentane, etc. A useful ha logenated hydrocarbon is e.g. B. CH ₂ Cl ₂ .

The blowing agent compositions preferably contain 5 to 95% by weight of 1,1,1,3,3-pentafluorobutane, in particular 10 up to 70% by weight.

Also suitable for use in the process according to the invention are blowing agent compositions which, in addition to HFC-365mfc and one or more of the fluorocarbons or hydrocarbons indicated above, also contain liquefied carbon dioxide. Then preferably 2 to 50% by weight of CO _{2 are contained} in the blowing agent composition. In addition, the blowing agent composition can also contain up to 30% by weight of additives which modify the properties of the plastic to be produced.

Very suitable as blowing agents are, for. B. The following are the compositions that can contain or consist of (examples of compositions with the parts by weight in parentheses):

• - HFC-365mfc and HFC-152a (70:30);
• - HFC-365mfc and HFC-32 (70:30);
• - HFC-365mfc, HFC-152a and CO ₂ (60: 30: 10);
• - HFC-365mfc, HFC-32 and CO ₂ (60: 30: 10);
• - HFC-365mfc, HFC-152a and butane (60: 30: 10);
• - HFC-365mfc, HFC-32 and butane (60: 30: 10);
• - HFC-365mfc, HFC-152a and HFC-134a (60: 25: 15);
• - HFC-365mfc, HFC-32 and HFC-134a (60: 25: 15);
• - HFC-365mfc and dimethyl ether (80:20);
• - HFC-365mfc and pentane (50:50);
• - HFC-365mfc and propane (70:30);
• - HFC-365mfc and Ethan (90:10);
• - HFC-365mfc, pentane and CO ₂ (45: 45: 10);
• - HFC-365mfc, butane and CO ₂ (50:40:10);
• - HFC-365mfc, propane and CO ₂ (70: 20: 10);
• - HFC-365mfc, ethane and CO ₂ (90: 5: 5).

Preferred blowing agent compositions contain 1,1,1,3,3-pentafluorobutane and / or difluoromethane 1,1-difluoro ethane, or they consist of these compounds. Very special compositions are used which contain 10 to 70 wt .-% of the HFC-365mfc and 90 to 30% by weight of the HFC-152a or HFC-32 contain or consist of.  

The flame retardants which can be used extremely well include, for example, reactive flame retardants such as brominated polyols. Flame retardants based on organic phosphorus compounds, for example phosphate esters and phosphonic esters, are also suitable. These have organic groups, which can also be substituted by one or more halogen atoms. The organic groups can have aliphatic or aromatic character. Phosphate esters and phosphonate esters which are substituted by three C ₁ -C ₆ -alkyl groups which may have one or two halogen atoms, for example trischloroisopropyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, dimethyl ethyl phosphate, tris dichloroisopropyl phosphate, preferably dimethyl methyl phosphate, are preferably very suitable .

One embodiment of the process according to the invention for the production of polyurethane foams provides that if a) HFC-365mfc and b) 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1,1,3,3-pentafluoropropane (HFC-245fa); 1,1,1,3,3,3-hexafluoropropane (HFC-236fa); or 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), but no CO ₂ , low-boiling, optionally halogenated hydrocarbons, ethers or halogenated ethers are contained, the blowing agent composition less than 50 wt. -% of 1,1,1,3,3-pentafluorobutane and more than 50% by weight of 1,1,1,2-tetrafluoroethane; 1,1,1,3,3-penta fluoropropane; Contains or consists of 1,1,1,3,3,3-hexafluoropropane or 1,1,1,2,3,3,3-heptafluoropropane.

The effective amount of propellant composition that one uses in the process according to the invention can by a multiple manual tests can be determined. It will be advantageous Blowing agent composition in an amount of 1 to 50 wt .-%, based on the total mix of art to be foamed  substance or the preliminary products (polyol, isocyanate, auxiliary agents) and blowing agent composition used.

Another object of the invention are in essence Chen closed-cell polyurethane foams that through a content of those to be used in the process according to the invention Propellant composition is characterized in the cells.

According to the invention, rigid foam, but also flexible foam, can be used manufacture isocyanate-based fabrics. The production sol cher foams and the base materials that can be used for them and the type of foam production are used in European Patent application EP-A-0 381 986; in "Ullmanns Encyclopedia of Industrial Chemistry ", 5th edition, volume A21, pages 665-680; international patent applications WO 92/00345, 96/30439, 96/14354 and the German published application DE 44 22 714 A1 discloses. Polyisocyanates are added for example with 2 to 4 isocyanate groups.

They have an aliphatic hydrocarbon residue up to 18 carbon atoms, a cycloaliphatic hydrocarbon residue of up to 15 carbon atoms, an aromatic carbon hydrogen residue with 6 to 15 carbon atoms or an araliphati hydrocarbon residue with 8 to 15 carbon atoms. Tech nisch particularly preferred starting components are in for example 2,4- and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate and their Mi worked. So-called "modified polyisocya nate "are used, which carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea contain groups or biuret groups.

Other starting components are connections with min at least 2 hydrogen reactive towards isocyanates atoms. In particular, there are connections with egg  nem molecular weight from 400 to 10,000, which preferably Have 2 to 8 hydroxyl groups and also amino groups, May have thiol groups or carboxyl groups.

If necessary, other auxiliaries and additives can also be used. For example, you can also che mix blowing agents such as water or other volatile uses organic substances as physical blowing agents Zen. Catalysts such as, for example, can also be used tertiary amines, such as dimethylcyclohexylamine, and / or organi metal compounds such as tin salts from Car Bon acids. Surface-active additives such as Emul gators or foam stabilizers, for example siloxane po lyether copolymers are used, reaction retarders, Cell regulators such as paraffins, fatty alcohols or dimethyl polysi loxanes, pigments, dyes, flame retardants such as phosphate esters or phosphonate esters, such as trischloriso propyl phosphate. Stabilizers can also be used against aging and weather influences, plasticizers, fillers substances, dyes, antistatic agents, nucleating agents, pores regulator substances or biocidally active substances.

Suitable catalysts are for example in the international patent application WO 96/14354 called. To include organic amines, amino alcohols and amino ethers such as Morpholine compounds, for example dimethylcyclohexylamine, Diethanolamine, 2-dimethylaminoethyl-3-dimethylaminopropyl ether, 2-dimethylaminoethyl ether, 2,2-dimorpholinodiethyl ether, N, N-dimethylaminoethylmorpholine, N-dimethylmorpholine. Organometallic compounds such as tin, Cobalt or iron compounds are useful as catalysts gate. Tin dioctoate, cobalt, for example, can be used naphthenate, dibutyltin dilaurate and iron acetonylacetate.  

The blowing agents can contain auxiliaries and additives such as water, one or more catalysts, flame retardant tel, emulsifiers, foam stabilizers, binders, crosslinking agents agents, UV stabilizers, nucleating agents and agents if necessary, further propellants. The blowing agent can e.g. B. the Propolymers of polyol and poly or diisocyanate added which is then foamed.

The first advantage of the method according to the invention is that that the blowing agent composition used, also belongs to the invention, favorable properties in terms of Owns ODP, GWP and Photosmog. Compared to polyurethane foams made with pure hydrocarbons as blowing agents have been produced, stand out after the Foam produced by the method according to the invention a better coefficient of thermal conductivity.

A particular advantage of that according to the invention Process available polyurethane foams come at tie far temperatures, mostly below about 15 ° C, for Carry. Surprisingly, after the invention polyurethane foams obtainable according to the process only a more favorable coefficient of thermal conductivity (i.e. heat transfer is lower) than foams made from pure hydro fabrics were produced, but rather compared to foam substances that is made with pure pentafluorobutane (HFC-365mfc) Thermal conductivity lower. In largely closed cells Polyurethane foams with blowing agent mixtures, wel che pentafluorobutane, preferably 1,1,1,3,3-pentafluorobutane and at least 1 of the other blowing agents mentioned above point, makes with regard to the coefficient of thermal conductivity, d. H. of the Thermal insulation ability a synergistic effect of the use blowing agent mixtures noticeable. The using of pentafluorobutane, preferably HFC-365mfc and at least another of the blowing agents specified above  As a result, polyurethane foams are particularly suitable good for insulation against cold in a temperature range below half of about 15 ° C.

example Manufacture of PU foams

To produce the PUR foam was considered an out a polyol mixture consisting of 40 Ge parts of an ethylenediamine / propylene oxide polyether (OH- Number 480), 60 parts by weight of a sorbitol / glycerin / propylene oxide polyether (OHZ 490), 1 part by weight of foam stabilizer (Type DC 193 from Dow Corning Corp.) and 1.5 parts by weight of Di methylcyclohexylamine used. Diphenylmethane diisocyanate was increased as an isocyanate component by 10% by weight stoichiometric amount used.

The PUR foams were made on a low pressure system a discharge rate of approx. 8 kg / min. with the one dose 3 components is possible. As a mixing day gregat served a static mixer.

a) Using HFC-365mfc / 152a

According to the invention, a blowing agent composition was used in an amount of 30 parts by weight, based on the polyol component. According to the blowing agent composition consisted of 70 parts by weight of HFC-365mfc and 30 parts by weight of HFC-152a. In addition, 1 part by weight of water was also used as a chemical blowing agent. With the blowing agent composition according to the invention, a rigid PU foam with a fine-cell structure and a density of approx. 32 kg / m ³ with low shrinkage was produced.

b) Use of HFC-365mfc / 32

According to the invention, a blowing agent composition was used in an amount of 30 parts by weight, based on the polyol component. According to the invention, the blowing agent composition consisted of 80 parts by weight of HFC-365mfc and 20 parts by weight of HFC-32. In addition, 1 part by weight of water was also used as a chemical blowing agent. With this blowing agent composition according to the invention, a rigid PU foam with a fine-cell structure and a density of approx. 28 kg / m ³ with low shrinkage was produced.

c) Use of HFC-365mfc / 152a / CO ₂

According to the invention, a blowing agent composition in an amount of 22 parts by weight, based on Polyolkom component used. According to the invention, the blowing agent existed composition of 70 parts by weight of HFC-365mfc and 30 parts by weight of HFC-152a. In addition to the The blowing agent composition was according to - DE 44 39 082 - 8 parts by weight of liquefied carbon dioxide also used. Furthermore, 1 part by weight of water was used as a chemical blowing agent medium used.

With the blowing agent composition according to the invention, a rigid PU foam with a fine-cell structure and a density of approx. 26 kg / m ³ with low shrinkage was produced.

Claims (9)

1. A process for the production of polyurethane foams, characterized in that a composition is used as blowing agent which comprises a) pentafluoropropane, preferably 1,1,1,3,3-pentafluoropropane (HFC-245fa) and / or pentafluorobutane, preferably 1 , 1,1,3,3-pentafluorobutane (HFC-365mfc) and b) at least one further blowing agent selected from the group comprising low-boiling, optionally halogen-substituted hydrocarbons, ethers and halogen ethers; Di fluoromethane (HFC-32); Difluoroethane, preferably 1,1-difluoroethane (HFC-152a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1,2-tetrafluoroethane (HFC-134a); Pentafluoropropane, preferably 1,1,1,3,3-pentafluoropropane (HFC-245fa); Hexafluoropropane, preferably 1,1,2,3,3,3-hexafluoropropane (HFC-236ea) or 1,1,1,3,3,3-hexafluoropropane (HFC-236fa); Heptafluoropropane, preferably 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) ent or consists thereof. 2. The method according to claim 1, characterized in that that compositions are used which 5 to 95 wt .-% HFC-365mfc included. 3. The method according to claim 1, characterized in that the blowing agent used is one of the following compositions which contain or consist of: HFC-365mfc and HFC-152a; HFC-365mfc and HFC-32; HFC-365-mfc, HF-152a and CO ₂ ; HFC-365mfc, HFC-32 and CO ₂ ; HFC-365mfc, HFC-152a and butane; HFC-365mfc, HFC-32 and butane; HFC-365mfc, HFC-152a and HFC-134a; HFC-365mfc, HFC-32 and HFC-134a; HFC-365mfc and dimethyl ether; HFC-365mfc and pentane; HFC-365mfc and propane; HFC-365mfc and ethane; HFC-365mfc, pentane and CO ₂ ; HFC-365mfc, butane and CO ₂ ; HFC-365mfc, propane and CO ₂ ; HFC-3E5mfc, ethane and CO ₂ . 4. The method according to claim 3, characterized in that compositions are used which contain 10 to 70% by weight of HFC 365mfc and 90 to 30 wt .-% of the other component (s), esp contain special HFC-32 and / or HFC-152a or best of them hen. 5. The method according to claim 1, characterized in that the blowing agent composition additionally contains 2 or 50 wt .-% CO ₂ . 6. The method according to claim 1, characterized in that the blowing agent composition up to 30 wt .-% of the Properties of the plastic modifying additives ent holds, especially flame retardants or plasticizers. 7. The method according to claim 1, characterized in that the blowing agent composition in an amount of 1 up to 50 wt .-%, based on the total mixture of polyurethane and blowing agent composition. 8. Mainly closed-cell polyurethane foams, characterized by a propellant content together settlement, the a) pentafluoropropane, preferably 1,1,1,3,3- Pentafluoropropane (HFC-245fa), and / or pentafluorobutane preferably 1,1,1,3,3-pentafluorobutane (HFC-365mfc), and b) min Another blowing agent selected from the group comprising low-boiling, optionally halogen-substituted hydrocarbons, ethers and halogen ethers; Difluoromethane (HFC-32); Difluoroethane, preferably 1,1-difluoroethane (HFC- 152a); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1,2-tetrafluoro ethane (HFC-134a); Pentafluoropropane, preferably 1,1,1,3,3- Pentafluoropropane (HFC-245fa); Hexafluoropropane, preferably 1,1,2,3,3,3-hexafluoropropane (HFC-236ea) or 1,1,1,3,3,3- Hexafluoropropane (HFC-236fa); Heptafluoropropane, preferably  1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) contains or is consists of. 9. Blowing agent mixture, usable for the production of PU foams with improved properties regarding Thermal conductivity at low temperatures, containing or consisting of 1 to <50 wt .-% 1,1,1,3,3-pentafluorobutane and <50 to 99% by weight of at least one fluorocarbon selected from the group consisting of 1,1,1,2-tetrafluoro ethane, 1,1,1,3,3-pentafluoropropane, 1,1,1,3,3,3-hexafluoroprop pan and 1,1,1,2,3,3,3-heptafluoropropane.