Preparation method and application of a macromolecular stabilizer

Abstract

The application discloses a preparation method and application of a macromolecular stabilizer. After a base polyether is reacted with an alkali, a halogenated hydrocarbon is added for end capping; then the end capping product is reacted with an anhydride and an end capping agent to generate the macromolecular stabilizer. Compared with traditional stabilizers, the stabilizer synthesized by the method can reduce the solubility of polystyrene-acrylonitrile particles in DCM (dichloromethane) in a polymer polyol, and further improve the filtering performance of the polymer polyol after being mixed with DCM, so that the equipment is not prone to being blocked.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer polyols, and particularly relates to a preparation method and application of a stabilizer for preparing polymer polyols. BACKGROUND

[0002] Compared with polyether polyols, polymer polyols have higher hardness of polyurethane foams, and are mainly used for high resilience, high bearing and molded foams, and are widely used in the fields of automobile seats, mattresses, furniture and the like.

[0003] The polymer polyols are mainly dispersions of a blend of styrene and acrylonitrile in polyether polyols, and the dispersion stability of organic solid particles in the polyether polyols is ensured by a macromolecular stabilizer. The macromolecular stabilizer also determines the surface properties of the organic solid particles in the polymer polyols to a certain extent.

[0004] In the foaming process of polyurethane foams, a small amount of blowing agent needs to be added to help form the foams. The blowing agent includes chemical blowing agents and physical blowing agents. The chemical blowing agents include water and other substances that can react with isocyanate to generate gas; and the physical blowing agents are substances such as dichloromethane, which have a relatively low boiling point and are vaporized after the exothermic reaction of isocyanate and polymer polyols.

[0005] At present, a common macromolecular stabilizer is usually synthesized from a 3-6 functionality unblocked base polyether and an acid anhydride and an epoxy compound. The base polyether part has good compatibility with polyether, and the acid anhydride and epoxy compound part provides aromatic rings or double bonds to combine with styrene / acrylonitrile, so as to ensure the dispersion stability of styrene / acrylonitrile solid particles in the polyether.

[0006] When this stabilizer is used to synthesize polymer polyols, due to the presence of hydroxyl groups on the surface of the organic solid particles, fibrous solids are precipitated after mixing with the blowing agent dichloromethane (DCM), thereby blocking the filter and affecting downstream use. SUMMARY

[0007] To solve the above problems, the present application provides a preparation method and application of a new macromolecular stabilizer, so that the polymer polyols synthesized therefrom will not precipitate solids when mixed with the blowing agent DCM, meet the filtration requirements, and do not block the equipment.

[0008] A preparation method of a macromolecular stabilizer, comprising the following steps:

[0009] (1) After the base polyether is reacted with a base, a halogenated hydrocarbon is added for blocking.

[0010] (2) The blocked product obtained in step (1) is reacted with an acid anhydride and a blocking agent to generate a macromolecular stabilizer.

[0011] Preferably, the base polyether in step (1) is a high molecular polyether polyol obtained by initiating ring-opening reaction of an epoxy compound with a small molecule polyol in the presence of a catalyst. Preferably, the small molecule polyol is glycerol, trimethylolpropane, pentaerythritol, hexitol, sorbitol, and the epoxy compound is ethylene oxide and propylene oxide.

[0012] Preferably, the base polyether in the present application has a molecular weight of 3000-12000, preferably 10000-12000, and a functionality n of 3-8, preferably 5-6.

[0013] Before the base polyether is capped with a halogenated hydrocarbon in the present application, the alcohol hydroxyl groups of the base polyether need to be converted into alkali or alkaline earth metal alcoholates. Preferably, the base in step (1) can be an alkali metal, an alkaline earth metal, an alkali metal or alkaline earth metal hydroxide, an alkali metal or alkaline earth metal alcoholate, preferably an alkali metal alcoholate, which is used in an amount related to the functionality n of the base polyether, with a molar ratio of base to base polyether of 1:1-1.3n:1, preferably n:1-1.2n:1. After the addition of the base, the base polyether needs to be devolatilized to form the alcoholate.

[0014] The reaction temperature of the base polyether with the base is 80-120°C, preferably 100-120°C. The devolatilization vacuum is preferably 80-100 kPa. The devolatilization time is 1-5 h, preferably 3-5 h.

[0015] To cap the base polyether, the halogenated hydrocarbon needs to be reacted with the alcoholate to form a hydrocarbon-capped polyether. Preferably, the halogenated hydrocarbon is a C1-C3 aliphatic monohalide, preferably methyl chloride and chloroethane, which is used in an amount of 1-2 times, preferably 1.1-1.5 times, the molar amount of the added base.

[0016] The reaction temperature of the alcoholate with the halogenated hydrocarbon is 60-180°C, preferably 70-90°C. The reaction time is 1-5 h, preferably 1-1.5 h. After the reaction is complete, the unreacted halogenated hydrocarbon is removed by devolatilization.

[0017] In step (1), the capped base polyether is adjusted to a pH of 6-8, adsorbed and dehydrated, and then filtered to remove the salt to obtain the capping product.

[0018] Preferably, in step (2), the anhydride is an anhydride containing an aromatic ring or a double bond, preferably maleic anhydride, phthalic anhydride, succinic anhydride, and itaconic anhydride, etc. The molar amount of the anhydride added is 0.8-1.5 times, preferably 1-1.5 times, the molar amount of the base polyether. The reaction temperature of the anhydride with the capped product is 85-100°C.

[0019] In step (2), the capped product obtained in step (1) is first reacted with the anhydride, and then the reaction product is reacted with the capping agent.

[0020] In the step (2), the end-capping agent is a substance containing an epoxy group, preferably oxirane, oxetane, epoxystyrene and glycidyl methacrylate, and the amount of the end-capping agent added is 0.8-1.5 times, preferably 1-1.5 times, the molar amount of the base polyether. After the reaction, a devolatilization treatment is needed. In the step (2), the temperature of the end-capping reaction is 80-160°C, preferably 100-120°C.

[0021] A polymer polyol, which is prepared by the preparation method of the present application.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] By alkyl end-capping the base polyether in the stabilizer, the content of the hydroxyl group on the surface of the solid particles in the POP is reduced, and thus the polarity of the solid surface is reduced. After the reduction of the polarity of the solid surface, the mixed dichloromethane blowing agent with high polarity will not separate out fibrous solids in the POP, and the filtration performance is good. The POP prepared by the end-capped and modified stabilizer is very suitable for the premixed dichloromethane filtration blowing process, and the problem of clogging the gun head will not occur. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Polymer polyol A and DCM mixed filtration effect diagram.

[0025] Figure 2 Polymer polyol B and DCM mixed filtration effect diagram.

[0026] Figure 3 Polymer polyol C and DCM mixed filtration effect diagram.

[0027] Figure 4 Polymer polyol D and DCM mixed filtration effect diagram.

[0028] Figure 5 Polymer polyol E and DCM mixed filtration effect diagram. DETAILED DESCRIPTION

[0029] Base polyether a: a polyether prepared by reacting sorbitol with a functionality of 6 with propylene oxide and oxirane, the content of oxirane being 18%, and the molecular weight being 12000.

[0030] Base polyether b: a polyether prepared by reacting glycerol with a functionality of 3 with propylene oxide and oxirane, the content of oxirane being 10%, and the molecular weight being 4800.

[0031] Base polyether c: polyether prepared by reacting a raw material alcohol with an average functionality of 5, which is a mixture of glycerol with a functionality of 3 and sorbitol with a functionality of 6, with ethylene oxide and propylene oxide, ethylene oxide content 12%, molecular weight 9350.

[0032] Example 1

[0033] Base polyether a 502 g and a 30% by mass methanol solution of potassium methoxide 44 g were charged into a reaction kettle, vacuumed to -0.1 MPa while stirring, and then de-methanated at 110°C for 3 h. After cooling to 90°C, chloromethane 18 g was added, and the reaction was carried out for 1.5 h. After removing the unreacted chloromethane under vacuum, neutralization and desalting were performed for purification. The hydroxyl value of the capped base polyether was measured to be 13 mgKOH / g, and the calculated capping rate was 52%.

[0034] Capped polyether 360 g after purification was added with 0.022 g of a 50% KOH solution, and vacuum dehydration was carried out for 2 h. Maleic anhydride 4.38 g was added, and after the reaction was carried out for 3 h, ethylene oxide 1.9 g was added. After aging and devolatilization, capped macromolecular stabilizer A was obtained.

[0035] Example 2

[0036] Base polyether a 667 g and a 30% by mass methanol solution of potassium methoxide 75 g were charged into a reaction kettle, vacuumed to -0.1 MPa while stirring, and then de-methanated at 115°C for 3 h. After cooling to 90°C, chloromethane 21 g was added, and the reaction was carried out for 1.5 h. After removing the unreacted chloromethane under vacuum, neutralization and desalting were performed for purification. The hydroxyl value of the capped base polyether was measured to be 6 mgKOH / g, and the calculated capping rate was 78%.

[0037] Capped polyether 360 g after purification was added with 0.022 g of a 50% KOH solution, and vacuum dehydration was carried out for 2 h. Maleic anhydride 3.5 g was added, and after the reaction was carried out for 3 h, ethylene oxide 1.7 g was added. After aging and devolatilization, capped macromolecular stabilizer B was obtained.

[0038] Example 3

[0039] Base polyether b 667 g and a 30% by mass methanol solution of sodium methoxide 52 g were charged into a reaction kettle, vacuumed to -0.1 MPa while stirring, and then de-methanated at 115°C for 3.5 h. After cooling to 90°C, chloromethane 26 g was added, and the reaction was carried out for 1.5 h. After removing the unreacted chloromethane under vacuum, neutralization and desalting were performed for purification. The hydroxyl value of the capped base polyether was measured to be 15.1 mgKOH / g, and the calculated capping rate was 56.7%.

[0040] Take the refined end-capped polyether 360 g, add 0.022 g of 50% KOH solution, vacuum dehydration for 2 h. Add itaconic anhydride 4.8 g, after 3 h of reaction, add glycidyl methacrylate 6.3 g, after aging and devolatilization, end-capped macromolecular stabilizer D is obtained.

[0041] Example 4

[0042] The base polyether c 667 g and 68 g of 30% mass fraction sodium methoxide methanol solution were added to the reaction kettle, stirred and vacuumed to-0.1 MPa, and the temperature was raised to 110 ℃ to remove methanol for 3.5 h. After cooling to 90 ℃, 36 g of chloroethane was added and reacted for 1.5 h. After vacuum removal of unreacted chloromethane, neutralization and desalination for purification. The hydroxyl value of the end-capped base polyether is 7.2 mg KOH / g, and the calculated end-capping rate is 76%.

[0043] Take the refined end-capped polyether 360 g, add 0.022 g of 50% KOH solution, vacuum dehydration for 2 h. Add itaconic anhydride 4.8 g, after 3 h of reaction, add glycidyl methacrylate 6.3 g, after aging and devolatilization, end-capped macromolecular stabilizer D is obtained.

[0044] Comparative Example 1

[0045] Directly take the base polyether (not end-capped, hydroxyl value is 28 mg KOH / g) 360 g, add 0.022 g of 50% KOH solution, vacuum dehydration for 2 h. Add maleic anhydride 4.38 g, after 3 h of reaction, add ethylene oxide 1.9 g, after aging and devolatilization, end-capped macromolecular stabilizer E is obtained.

[0046] The macromolecular stabilizers prepared in Examples 1-4 and Comparative Example 1 were respectively made into polymer polyols with a solid content of 45%. 100 g of polymer polyol was mixed with 10 g of dichloromethane, and then left to stand for 6 h. The passing rate was measured by passing through a 150 mesh filter screen, as shown in Table 1.

[0047] Table 1 Basic indicators of polymer polyols

[0048]

[0049] As Figures 1-5 The DCM filtration performance diagrams of polymer polyols A, B, C, D and Comparative Example E, respectively. A large amount of fibrous solid is formed after adding DCM in Comparative Example E, which is difficult to filter; compared with the comparative example, the DCM filtration performance of the end-capped polymer polyol is improved, and the amount of residue on the filter screen after filtration of the polymer polyol B with high end-capping rate is less than that of polymer polyols A, C and D, and the DCM filtration performance is better.

Claims

1. A process for the preparation of a macromolecular stabilizer, characterized by, The method comprises the following steps: (1) reacting a base polyether with a base, and then adding a halogenated hydrocarbon to end-cap; (2) reacting the end-capped product obtained in step (1) with an acid anhydride and an end-capping agent to form a macromolecular stabilizer; In step (1), the base polyether is a high-molecular polyether polyol obtained by ring-opening reaction of an epoxy compound in the presence of a catalyst using a small-molecular polyol as an initiator; The molar ratio of the base to the base polyether is 1:1-1.3n:1, wherein n is the functionality of the base polyether; The amount of the halogenated hydrocarbon is 1-2 times the molar amount of the added base.

2. The production method according to claim 1, characterized by, The small-molecular polyol is glycerol, trimethylolpropane, pentaerythritol, hexitol, or sorbitol, and the epoxy compound is ethylene oxide or propylene oxide.

3. The production method according to claim 1 or 2, characterized by, The base polyether has a molecular weight of 3000-12000 and a functionality n of 3-8.

4. The production method according to claim 3, characterized by, The base polyether has a molecular weight of 10000-12000 and a functionality n of 5-6.

5. The preparation method according to claim 1, characterized in that, In step (1), the base is an alkali metal, an alkaline earth metal, a hydroxide of an alkali metal or an alkaline earth metal, or an alcoholate of an alkali metal or an alkaline earth metal.

6. The production method according to claim 5, wherein In step (1), the base is an alcoholate of an alkali metal.

7. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of the base to the base polyether is n:1-1.2n:

1.

8. The method of claim 1, wherein, The reaction temperature of the base polyether with the base is 80-120°C.

9. The preparation method according to claim 8, characterized in that, The reaction temperature of the base polyether with the base is 100-120°C.

10. The method of claim 1, wherein, The halogenated hydrocarbon is a fatty hydrocarbon monohalide having 1-3 carbon atoms.

11. The method of claim 10, wherein, The halogenated hydrocarbon is selected from methyl chloride and ethyl chloride, and the amount thereof is 1.1-1.5 times the molar amount of the added base.

12. The method of claim 1, wherein, The end-capping reaction temperature of the halogenated hydrocarbon is 60-180°C, and the reaction time is 1-5 hours.

13. The method of claim 12, wherein, The end-capping reaction temperature of the halogenated hydrocarbon is 70-90°C, and the reaction time is 1-1.5 hours.

14. The method of claim 1, wherein, In step (1), the end-capped base polyether is adjusted to a pH of 6-8, adsorbed and dehydrated, and then filtered to remove salts to obtain the end-capped product.

15. The method of claim 1, wherein, In step (2), the acid anhydride is an acid anhydride containing an aromatic ring or a double bond.

16. The method of claim 15, wherein, In step (2), the acid anhydride is maleic anhydride, phthalic anhydride, succinic anhydride, or itaconic anhydride.

17. The method of claim 1, wherein, The molar amount of the added acid anhydride is 0.8-1.5 times the molar amount of the base polyether.

18. The method of claim 17, wherein, The molar amount of the added acid anhydride is 1-1.5 times the molar amount of the base polyether.

19. The method of claim 1, wherein, The reaction temperature of the acid anhydride with the end-capped product is 85-100°C.

20. The method of claim 1, wherein, In step (2), the end-capped product obtained in step (1) is first reacted with the acid anhydride, and then the reaction product is reacted with the end-capping agent.

21. The method of claim 1, wherein, In step (2), the end-capping agent is a substance containing an epoxy group.

22. The method of claim 21, wherein, In step (2), the end-capping agent is ethylene oxide, propylene oxide, epoxy styrene, or glycidyl methacrylate.

23. The method of claim 1, wherein, The amount of the added end-capping agent is 0.8-1.5 times the molar amount of the base polyether.

24. The method of claim 23, wherein, The amount of the added end-capping agent is 1-1.5 times the molar amount of the base polyether.

25. The method of claim 1, wherein, In step (2), the end-capping reaction temperature is 80-160°C.

26. The method of claim 25, wherein, In step (2), the end-capping reaction temperature is 100-120°C.

27. A polymeric polyol, which is a macromolecular stabilizer prepared by the method of any one of claims 1-26.

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