CN1039420C - A kind of preparation method of polymer stabilizer with self-synergistic effect - Google Patents

Abstract

The invention relates to a preparation method of a polymer light stabilizer with a self-synergistic effect, which has hindered amine (HA) and o-hydroxybenzophenone (HBP) groups on the side chain. It uses ethylenically unsaturated monomers containing 2,2,6,6-tetramethylpiperidine (hindered amine-HA) and 2-hydroxybenzophenone (HBP) photostabilizing groups respectively, through free radicals Made by polymerization. The photostability test of polymers shows that the polymer photostabilizer prepared by the method of the invention has obvious synergistic effect. The self-synergistic macromolecular light stabilizer prepared by the invention is a brand-new light stabilizing assistant.

Description

The invention relates to a preparation method of a novel high molecular light stabilizer with a self-synergistic effect and a hindered amine (HA) and an o-hydroxybenzophenone (HBP) group on the side chain.

Hindered amine compounds have been widely used as high-efficiency light stabilizers in the stabilization of various synthetic polymers (U.S.P4,038,280). Recently, a class of hindered amine light stabilizers with higher molecular weight has been adopted to obtain a more satisfactory light stabilization effect (U.S.P4,233,412; "Polymer Communication" 5,285 (1979)). The mixed use of different types of light stabilizers can often achieve a higher light stabilization effect than when they are used alone, that is, a synergistic effect. The hindered amine light stabilizer itself does not absorb) 2900A ultraviolet light. Therefore, their synergistic effect when mixed with ultraviolet absorbers such as o-hydroxybenzophenones has been extensively developed (U.S.P4,110,304; ApplPolym.Sci.vol.27, 2761 vol.(1982) But in past work, hindered amine light stabilizer and o-hydroxybenzophenone ultraviolet absorber all are to form light stabilizing system with the form of mixture.At this moment, often exist some unavoidable shortcoming, as (1) due to Their respective molecular weights and chemical properties are different, so they are different from the compatibility of the stabilized polymer and the dispersibility therein. Therefore it is difficult to ensure that they maintain a uniform and constant relative composition ratio in the polymer; (2) because they The thermal properties of each are different, so the heat loss during processing is also different, so it is not easy to maintain the stability of the initial relative concentration. As a result, the light stabilization effect is often not ideal.

In order to overcome the above-mentioned shortcoming, the present inventor once reported a novel macromolecular light stabilizer with self-synergistic effect that HA and HBP are linked in the same molecule by chemical bonding, (The 6thChina-Japan Symposium on Radical Polymerization, Guilin, China October 8-12.1991, P113) the purpose of the present invention is to provide the detailed preparation method of the above-mentioned polymer light stabilizer with self-synergistic effect:

The self-synergistic macromolecular light stabilizer of the present invention contains two kinds of light stabilizing groups, HA and HBP. They are connected as side chains in the same polymer light stabilizer molecule. To be exact, the said self-synergistic macromolecular light stabilizer of the present invention is a kind of copolymer with HA and HBP light stabilizing group in side chain, and such copolymer is made of vinylic monomers with HA and HBP respectively. prepared by copolymerization. During the copolymerization, a third monomer can also be added to adjust the compatibility between the prepared polymer light stabilizer and the stabilized polymer. Therefore, the self-synergistic macromolecular light stabilizer of the present invention is a binary copolymer prepared from olefinic monomers containing HA and HBP respectively, or it can be prepared by copolymerizing them with a certain third monomer (M ₃ ). The obtained terpolymers have HBP substituents of HA on their side chains respectively.

(受阻胺-HA)R₂为

The above-mentioned ethylenic monomers containing HA or HBP light stabilizing group are: where _R1 is

(Hindered amine-HA) R ₂ is

Monomer (I) is 4-allyloxy-2,2,6,6-tetramethylpiperidine (M _EHA ) and monomer (II) is 4-allyloxy-2-hydroxybenzidine The ketone (M _EHBP ) is prepared by reacting allyl bromide with 4-hydroxy-2,2,6,6-tetramethylpiperidine and 2,4-dihydroxybenzophenone, respectively.

The above-mentioned third monomer is an α-olefinic monomer (M ₃ ), which can be selected according to the performance of the stabilized polymer, and they include:

其中(R₃)为H，或-CH₃，R₄为1-18个碳的烷基；Acrylic or Methacrylate:

Wherein (R ₃ ) is H, or -CH ₃ , and R ₄ is an alkyl group with 1-18 carbons;

Styrene and its derivatives;

Maleic anhydride, acrylamide, acrylonitrile and vinyl acetate, etc.

The macromolecular light stabilizer with good self-synergistic coordination of the present invention is made by M _EHA , M _EHBP and M ₃ copolymerization, and the proportioning ratio (weight %) of three kinds of ethylenic monomers is M ₃ :( M _EHA +M _EHBP )=80-0: 20-100, but better with 70-0: 30-100, especially the best with 55: 45, wherein M _EHA : M _EHBP (weight %) can be 90-10 :10-90, but 80-20:20-80 is better, and the best ratio is 75:25.

The macromolecule photostabilizer of self-synergistic effect of the present invention is made by M _EHA : M _EHBP and _M3 by free radical copolymerization reaction, and used free radical copolymerization initiator is organic peroxide-peroxide ten Diacyl can also be azo compounds such as azobisisobutyronitrile, azobisisoheptanonitrile, etc. Their usage is usually 0.2-5%, preferably 0.5-3%, especially 1-2%, of the total weight of the reactants.

The preparation process of the self-synergistic effect macromolecular light stabilizer of the present invention is: according to the described proportioning ratio, take the required monomer and dissolve it in 2-4 times the organic solvent; add the free radical copolymerization initiator, under stirring carry out the polymerization reaction. The controlled temperature range is 50-90°C, preferably 60-70°C, and the reaction time is 6-10 hours. At the end of the reaction, the polymer is precipitated with 10-20 times of methanol, the solvent is separated and removed, and the resulting precipitated product is Drying is carried out to obtain the final product. If the polymer has precipitated out at the end of the reaction, there is no need to add methanol for precipitation, the solvent can be directly separated, and the product can be obtained by drying and precipitating.

The reaction medium used in the polymerization reaction obtained from the synergistic effect polymer light stabilizer in the present invention refers to benzene, any one in organic solvents such as toluene, chloroform, tetrahydrofuran, heptane, hexane, sherwood oil, and their consumption It is 2-4 times of the total amount of ethylenic monomers.

The polymer light stabilizer containing both HA and HBP groups on the side chain prepared by the method of the present invention and the corresponding polymer light stabilizer containing only HA or HBP groups respectively have carried out the photostability test of polypropylene, The comparison results show that under the condition of the same concentration of HA and HBP, the polymer light stabilizer prepared by the method of the present invention has better light stability and shows a significant synergistic effect.

The self-synergistic macromolecular light stabilizer produced by the inventive method can be used as the light stabilizer of various synthetic polymers, such as polyolefins or their copolymers; polyethylene, polypropylene, polybutene-1, Polybutadiene and ethylene-propylene copolymers, etc.; polystyrene and its copolymers, acrylic and methacrylate polymers and their copolymers, etc.

Example 1

In a reaction flask equipped with stirring, condenser and thermometer, add 17.8 grams of 4-allyloxy-2,2,6,6-tetramethylpiperidine (M _EHA ), 4-allyloxy - 2.5 grams of 2-hydroxybenzophenone (M _EHBP ) and the third monomer: 25.8 grams of vinyl acetate (VA), and then add 150 milliliters of benzene to make a solution. 0.5 g of azobisisobutyronitrile (AIBN) was added, and then the polymerization reaction was carried out at 80° C., and the reaction time was 10 hours. At the end of the reaction, the polymer was precipitated with 10 times the amount of methanol, and the obtained polymer was dried for elemental analysis and light stability measurement.

Example 2-6

Method is with embodiment 1, prepares the terpolymer containing M _EHA , M _EHBP and vinyl acetate (VA) with the proportioning listed in table 1:

Table 1 Example M _EHA M _EHBP VA Benzene AIBN

(grams) (grams) (grams) (ml) (grams)

2 15.8 5.1 25.8 150 0.5

3 14.8 6.4 25.8 150 0.5

4 13.0 8.4 25.8 150 0.5

5 10.0 12.7 25.8 150 0.5

6 3.9 20.3 25.8 150 0.5

Example 7-8

Prepare M _EHA -VA or M _EHBP -VA binary copolymer with the formula given in Table 2 as a comparison. Method is all the same as embodiment 1.

Table 2 Example M _EHA M _EHBP VA Benzene AIBN

(grams) (grams) (grams) (ml) (grams)

7 19.7 43.1 20 0.94

8 - 14.8 50 20 0.87

Example 9

A certain amount of terpolymers prepared in Examples 1-6 are made into benzene or acetone solution, and 10 grams of polypropylene powder without any additives are added to make the content 4× ^10-5 moles/10 grams PP (polypropylene). After removing the solvent, dry it thoroughly, and then make a film with a thickness of 100±10μ (compressing conditions: pressure 12MPa, temperature 185°C, time 1.5 minutes, cooling and quenching in cold water rapidly after film formation) The sample is placed under a 500W high-pressure mercury lamp (filter (2900 Å part) irradiation, track the carbonyl absorption of the sample at 1712 cm ^-1 with infrared spectroscopy regularly, and use the time τ when the carbonyl absorption reaches 0.01 as the photooxidation induction period of the sample crystal.

Carry out the test of photostability to the sample of embodiment 7-8 with the same method as above, the results are shown in Table 3.

I-VI represents in the table, each embodiment 1-6 sample forms six contrast groups with embodiment 7-8 sample respectively, in each contrast group, when using the sample of embodiment 1-6 as photostabilizer , the effective concentration of HA and HBP in the polypropylene sample sheet is equal to the effective concentration of HA or HBP in the polypropylene sample sheet when the sample of Example 7 or 8 is used as light stabilizer respectively. Moreover, the sum of the concentrations of HA and HBP is 4×10 ^-5 mol/10 g PP.

The synergistic effect can be expressed by the quantitative formula: S _A =U ₁₊₂ -(τ ₁ +τ ₂ )τ ₁ +τ ₂ (Polym.Photochem.3.235,1983), where τ represents the oxidation induction period of the polypropylene sample. τ ₁₊₂ represents the τ of the self-synergistic effect polymer light stabilizer of the present invention containing both HA and HBP, t ₁ represents the τ of the polymer light stabilizer containing only HA, and τ ₂ represents the polymer light stabilizer containing only HBP Tau of the agent. So when S _A =0 means additive effect, S _A <0 means anti-synergistic effect, and S _A >0 means synergistic effect. Using the oxidation induction period τ listed in Table 3, the synergistic effect _SA calculated by substituting the above formula is listed in the last item, and the results show that the polymer light stabilizer of the present invention has obvious self-synergistic effect.

table 3 No sample Content 10mol/10pp oxidation induction period Synergy S _A % I 1 Example 12 Comparative Example 73 Comparative Example 8 43.60.4 28019530 25 II 4 Embodiment 25 Comparative Example 76 Comparative Example 8 42.81.2 40017050 82 III 7 Embodiment 38 Comparative Example 79 Comparative Example 8 42.41.6 35015058 68 IV 10 Embodiment 411 Comparative Example 712 Comparative Example 8 422 30013464 52 V 13 Embodiment 514 Embodiment 715 Comparative Example 8 413 26012670 33 VI 16 Embodiment 617 Embodiment 718 Comparative Example 8 40.43.6 1505580 11

Claims (9)

1. a preparation method of a self-synergistic polymer light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) groups on the side chain, said light stabilizer is composed of monomer 4-ene Propoxy-2,2,6,6-tetramethylpiperidine (M _EHA ) and monomer 4-allyloxy-2-hydroxybenzophenone (M _EHBP ) and α-olefinic monomers as Prepared by copolymerization of the third monomer (M ₃ ), characterized in that the third type of monomer includes the general formula: Acrylic or methacrylic monomers wherein R ₃ is H or -CH ₃ , and R ₄ is an alkyl group with 1-18 carbons; Styrene and its derivatives; maleic anhydride; Acrylamide; Any one of acrylonitrile and vinyl acetate, the proportioning ratio (weight %) of three kinds of monomers is according to M ₃ : (M _EHA +M _EHBP )=80-0:20-100, Where M _EHA : M _EHBP = 90-10 : 10-90, Its preparation process is as follows: 1.1 Weigh the monomer according to the ratio and dissolve it in 2-4 times the organic solvent, 1.2 Add 0.2-5% free radical copolymerization initiator of the total weight of reactants, and then 1.3 Under stirring, polymerize at a temperature of 50-90°C and react for 6-10 hours, 1.4 At the end of the reaction, use 10-20 times of methanol to precipitate the polymer, 1.5 Separation and removal of solvent, 1.6 Dry the precipitated product. 2. as claimed in claim 1, the preparation method of the self-synergistic macromolecular light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the side chain is characterized in that described M ₃ : (M _EHA +M _EHBP )=70-0:30-100, where (M _EHA :M _EHBA )=80-20:20-80. 3. the preparation method of the self-synergistic macromolecular light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the side chain as claimed in claim 1, is characterized in that described M ₃ :(M _EHA +M _EHBP ) is 55:45, wherein M _EHA :M _EHBP is 75:25. 4. as claimed in claim 1, 2 or 3, have the preparation method of hindered amine (HA) and o-hydroxybenzophenone (HBP) group self-synergistic macromolecule light stabilizer on the side chain, it is characterized in that The organic solvent used in 1.1 can be any one of benzene, toluene, chloroform, tetrahydrofuran, heptane, hexane, and petroleum ether. 5. as claimed in claim 1, 2 or 3, the preparation method of the self-synergistic polymer light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the side chain, is characterized in that The amount of free radical copolymerization initiator added is 0.5-3% of the total weight of reactants. 6. on the side chain as claimed in claim 1,2 or 3, have the preparation method of hindered amine (HA) and o-hydroxybenzophenone (HBP) group self-synergistic macromolecule light stabilizer, it is characterized in that The free radical copolymerization initiator is 1-2% of the total amount of reactants. 7. as claimed in claim 1, 2 or 3, the preparation method of the self-synergistic polymer light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the side chain, is characterized in that The initiator used in 1.2 was lauryl peroxide. 8. as claimed in claim 1, 2 or 3, the preparation method of the self-synergistic polymer light stabilizer with hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the side chain, is characterized in that The initiator used in 1.2 is any one of azobisisobutyronitrile and azobisisoheptanonitrile. 9. as claim 1, 2 or 3 side chains have hindered amine (HA) and o-hydroxybenzophenone (HBP) group on the preparation method described in the self-synergistic macromolecular light stabilizer of group, it is characterized in that The reaction temperature in 1.3 is 60-70°C.