CN111718476A - A kind of mulching resin with controllable biodegradation cycle and preparation method thereof - Google Patents

Abstract

A mulching resin with controllable biodegradation cycle and a preparation method thereof belong to the field of high molecular weight mulching resin. The polymerized monomers of the mulching resin include: A: aliphatic dibasic acid and one or more mixtures of anhydrides, diesters, and diacid halides; B: unsaturated fatty acids and their multimers, acid anhydrides , one or more mixtures of acid halides; C: one or more mixtures of aromatic dibasic acids and their anhydrides, diesters, and diacid halides; D: one or more of aliphatic dihydric alcohols One or two or more of them are mixed; E: One or two or more of isocyanate, carbodiimide and epoxy compound chain extenders are mixed. The mulching resin is prepared by esterification of the above-mentioned polymerized monomers A, B, C and D under catalyst conditions, then through melt polycondensation or interfacial polymerization, and finally through melt chain extension reaction. The mulching resin of the invention has high molecular weight and excellent mechanical properties, and can control the material degradation period by adjusting the monomer ratio.

Description

A kind of mulching resin with controllable biodegradation cycle and preparation method thereof

technical field

The invention relates to a plastic film resin with controllable biodegradation period and a preparation method thereof, in particular to a high molecular weight plastic film resin with controllable biodegradation period and a preparation method thereof.

Background technique

Since the mulching technology was introduced into China in the 1970s, it has brought huge economic benefits to my country's agriculture. At the same time, it is difficult to recycle the plastic film and cause the residual plastic film pollution in the soil, which seriously affects the sustainable development strategy of my country's agriculture. The most effective way to solve the residual pollution of plastic film is to develop biodegradable plastic film, which can be completely degraded into carbon dioxide and water under natural conditions, and will not pollute the soil.

Commercial biodegradable mulching resins are polybutylene terephthalate-adipate (PBAT), polybutylene succinate (PBS), polybutylene succinate-adipate-butylene One or more of (PBSA), polylactic acid (PLA), the degradation cycle of this type of biodegradable plastic film resin is too fast under natural conditions, and it cannot meet the long-term requirements of crops to maintain moisture and water. Therefore, it is necessary to add antioxidants, ultraviolet absorption The degradation cycle of biodegradable mulch films can be regulated by using additives such as additives, UV stabilizers, etc., or through multi-layer co-extrusion and other processing technologies. Publication No. CN103665784A uses aromatic-aliphatic copolyester, polylactic acid, starch-based biodegradable materials, and adds ultraviolet light stabilizers and antioxidants to achieve biodegradation controllability of mulch films; Publication No. CN104072953A Degradable resin is compounded, and functional additives such as ultraviolet light stabilizer, ultraviolet absorber, antioxidant, anti-hydrolysis agent, chain extender and so on are added to realize the controllable degradation of the mulch film; the publication number CN104559087A regulates polylactic acid and polyterephthalic acid by regulating -Adipate-butanediol ratio, adding reactive additives, antioxidants, lubricants, UV absorbers, light stabilizers to solve the problem of the degradation cycle of mulch film; Publication No. CN109679299A uses PBAT as raw material, adding degradation rate adjustment agent and induction period regulator to achieve the purpose of controllable degradation. Adjuvants such as light stabilizers and UV absorbers are used in these patents, which are not only costly, but also have an impact on soil microorganisms. Publication numbers CN103587184A and CN105109165A both adopt a multi-layer co-extrusion process to make the mulch film meet the requirements of controllable degradation.

To sum up, the current biodegradable plastic film mainly uses PBAT and PLA compound, adding light stabilizers, UV absorbers, antioxidants and other auxiliary agents to control the plastic film degradation cycle, these processes are expensive to prepare plastic film, and they are harmful to soil microorganisms. influential.

SUMMARY OF THE INVENTION

The term "biodegradable plastic film" involved in the present invention means that the plastic film is completely converted into carbon dioxide and water by soil microorganisms under natural conditions such as light and moisture.

Aiming at the problems existing in the prior art, the present invention has the advantage of using a one-step method to prepare a biodegradable mulch film with high molecular weight, controllable biodegradation cycle and excellent mechanical properties.

The biodegradable period controllable mulching film resin of the present invention, the technical scheme for preparing the resin is as follows:

A mulching resin with a controllable biodegradation cycle, wherein the polymerized monomers of the mulching resin include:

A: one or more of aliphatic dibasic acids and their anhydrides, diesters, and diacid halides are mixed;

B: one or more mixtures of unsaturated fatty acids and their polymers, acid anhydrides and acid halides;

C: one or more mixtures of aromatic dibasic acids and their anhydrides, diesters, and diacid halides;

D: one or more mixtures of aliphatic diols;

E: One or two or more of isocyanates, carbodiimides, and epoxy compound chain extenders are mixed.

The mulching resin is prepared by esterification of the above-mentioned polymerized monomers A, B, C and D under catalyst conditions, then through melt polycondensation or interfacial polymerization, and finally through melt chain extension reaction.

The molar ratio of the sum of the functional groups of the polymerized monomers A, B and C to the functional group of the polymerized monomer D is 1:1-2;

The molar ratio of the polymerized monomer C to the total of the polymerized monomers A, B, and C is less than 60%;

The added amount of the chain extender E accounts for 10% or less of the mass percentage of the total polymerized monomers.

The number-average molecular weight of the plastic film resin is 40,000-70,000 g/mol, and the molecular weight distribution is 1.5-3;

The melt index of the plastic film resin is 3-5 g/10min, and the terminal carboxyl group is 5-20 mol/t.

Described polymerized monomer A is oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, tenacic acid One or two or more of dicarbondioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid and their anhydrides, diesters, and diacid halide derivatives are mixed.

The polymerized monomer B is oleic acid, linoleic acid, linolenic acid, arachidonic acid, 20-carbon-5-enoic acid, 22-carbon-6-enoic acid and its multimers, acid anhydrides, acid halide derivatives One or more of them are mixed.

Described polymerized monomer C is terephthalic acid, phthalic acid, isophthalic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 1,8- Naphthalenedicarboxylic acid and its anhydrides, diesters, diacid halide derivatives, or a mixture of two or more.

The polymerized monomer D is ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2-methylmethane 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl- 1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3 -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, One or more of polyoxyethylene, polyethylene glycol and polypropylene glycol are mixed.

Described polymerized monomer E is toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, dicyclohexylcarbon diisocyanate Imine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, ethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether , trimethylolpropane triglycidyl ether, furan methyl glycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A two One or more of glycidyl ether and resorcinol diglycidyl ether are mixed.

A preparation method of mulching resin with controllable biodegradation cycle, the steps of the method are:

(1) Mix the polymerized monomers A, B, C and D evenly, add a catalyst with a mass percentage of 0.01% to 0.5% to carry out the esterification reaction, and the system to be collected does not produce water, and the esterification stage is completed;

(2) then carry out the polycondensation reaction, when the melt index of the material rises to 15～50g/10min, the polycondensation reaction ends;

(3) Finally, a chain extension reaction is carried out, and a polymerized monomer E is added to carry out a melt chain extension reaction after step (2).

The esterification reaction temperature of the step (1) is 200～260° C., and the esterification reaction time is 1～3h;

The reaction catalyst in the step (1) is one or a mixture of two or more of Lewis acid, germanium-based compound, antimony-based compound, titanium-based compound, zinc-based compound, and tin-based compound.

The temperature of the polycondensation reaction in the step (2) is 230～250° C., the vacuum degree of the polycondensation reaction is 20～4000pa, and the polycondensation reaction time is 2～5h;

The temperature of the melt chain extension reaction in the step (3) is 150-230°C.

Compared with the prior art, the beneficial effects of the present invention:

(1) The biodegradable cycle-controllable plastic film resin polymerization monomers prepared by the present invention are all bulk industrialized commodities with low prices;

(2) The biodegradation cycle controllable mulch resin prepared by the present invention has high molecular weight and excellent mechanical properties, and the material degradation cycle can be regulated by adjusting the monomer ratio;

(3) The polymerization process of the present invention is simple, can be industrially produced, and the prepared mulch resin with a controllable biodegradation cycle has excellent and stable quality.

Detailed ways

The present invention is further described below in conjunction with the examples, and the scope of the present invention is not limited by these examples. The scope of the invention is set forth in the claims.

The molecular weight and molecular weight distribution of the polymer were determined by gel permeation chromatography, with chloroform as solvent, Waters-1525u instrument for testing, and polystyrene as the standard sample.

The acid-base titration method was used to test the terminal carboxyl groups of the polymer, and the test was carried out in accordance with the provisions of Method A in GB/T 14190-2008. The mixed solution is phenol-trichloromethane, and the volume ratio is 2:3. The standard titration solution is potassium hydroxide-benzyl alcohol with a concentration of 0.01 mol/L. Refer to 4.24 in GB/T 601-2002 for configuration and calibration. Bromophenol blue indicator concentration was 0.2%. Test preparation: 0.5g of sample was dissolved in 25.00ml of phenol-chloroform mixed solvent.

The melt index of the polymer was measured by a melt index meter. The test was carried out in accordance with the A regulation in GB/T3682-2000, and the test condition was D (temperature: 190°C, load 2.16kg).

The tensile property test of the polymer is carried out in accordance with the provisions of GB/T 17037.1-1997, and the A-type abrasive tool in GB/T 17037.1-1997 is used to prepare the 1A-type sample in GB/T 1040.2-2006. The state adjustment of the sample is carried out in accordance with the provisions of GB/T 2918-1998. The state adjustment conditions are 23±2℃, the relative humidity is 50%±10%, and the adjustment time is at least 40h but not more than 96h. The test is carried out in accordance with GB/T 1040.2-2006, and the test rate is 50mm/min.

Example 1

In the reaction kettle, add 3.94kg terephthalic acid, 1.38kg oleic acid polymer, 3.39kg adipic acid, 5.52kg ethylene glycol, add 7.7g tetrabutyl titanate, stir to carry out esterification reaction, temperature of reaction 200 ℃, when the system no longer generates water, the esterification reaction is completed; then the temperature is raised to 230 ℃, the vacuum degree is kept at 300pa, and the polycondensation reaction is carried out. Phenylmethane diisocyanate was subjected to melt chain extension reaction at 150°C to obtain biodegradable plastic film resin. The number average molecular weight of the polymer tested by GPC was 56,000, and the molecular weight distribution was 1.8.

Example 2

In the reaction kettle, add 3.57kg terephthalic acid, 2.51kg oleic acid polymer, 2.75kg adipic acid, 5.00kg ethylene glycol, add 7.7g tetrabutyl titanate, stir to carry out esterification reaction, temperature of reaction 200 ℃, when the system no longer generates water, the esterification reaction is completed; then the temperature is raised to 230 ℃, the vacuum degree is kept at 200pa, and the polycondensation reaction is carried out. Phenylmethane diisocyanate was subjected to melt chain extension reaction at 150°C to obtain biodegradable plastic film resin. The number average molecular weight of the polymer tested by GPC was 54,000, and the molecular weight distribution was 1.9.

Example 3

In the reaction kettle, add 3.01kg terephthalic acid, 4.24kg oleic acid polymer, 1.77kg adipic acid, 4.22kg ethylene glycol, add 7.7g tetrabutyl titanate, stir to carry out esterification reaction, temperature of reaction 200 ℃, when the system no longer generates water, the esterification reaction is completed; then the temperature is raised to 230 ℃, the vacuum degree is kept at 200pa, and the polycondensation reaction is carried out. Phenylmethane diisocyanate was subjected to melt chain extension reaction at 150°C to obtain biodegradable mulch resin. The number average molecular weight of the polymer tested by GPC was 55,000, and the molecular weight distribution was 1.8.

Example 4

In the reaction kettle, add 2.72kg terephthalic acid, 3.83kg oleic acid polymer, 1.60kg adipic acid, 5.53kg butanediol, add 7.7g tetrabutyl titanate, stir to carry out esterification reaction, temperature of reaction 220 ℃, when the system no longer produces water, the esterification reaction is completed; then the temperature is raised to 230 ℃, the vacuum degree is kept at 200pa, and the polycondensation reaction is carried out. Phenylmethane diisocyanate was subjected to melt chain extension reaction at 150°C to obtain biodegradable plastic film resin. The GPC test polymer had a number-average molecular weight of 53,000 and a molecular weight distribution of 1.8.

Comparative Example 1

Add 4.39kg of terephthalic acid, 4.18kg of adipic acid, 6.14kg of ethylene glycol into the reaction kettle, add 7.7g of tetrabutyl titanate, and stir to carry out esterification reaction. The reaction temperature is 200 ° C, and water is no longer generated in the system. , the esterification reaction is over; then the temperature is raised to 230°C, the vacuum degree is kept at 300pa, and the polycondensation reaction is carried out. After a period of reaction, a white polymer is obtained with a melt index of 24g/10min, 1% diphenylmethane diisocyanate is added, and 150°C Under the conditions of the melt chain extension reaction, the biodegradable mulch resin was obtained. The GPC test polymer had a number average molecular weight of 52,000 and a molecular weight distribution of 1.9.

Comparative Example 2

Add 3.80kg of terephthalic acid, 3.60kg of adipic acid, 7.70kg of butanediol to the reaction kettle, add 7.7g of tetrabutyl titanate, and stir to carry out esterification reaction. The reaction temperature is 220 ° C, until the system no longer generates water. , the esterification reaction was completed; then the temperature was raised to 230°C, the vacuum degree was kept at 300pa, and the polycondensation reaction was carried out. After a period of reaction, a white polymer was obtained with a melt index of 22g/10min, 0.9% diphenylmethane diisocyanate was added, and 150°C was added. Under the conditions of melt chain extension, the biodegradable mulching resin was obtained. The GPC test polymer had a number average molecular weight of 49,000 and a molecular weight distribution of 1.9.

The polymer mechanical properties are as follows:

sample name Melt index, g/10min Terminal carboxyl group, mol/t Tensile strength, MPa Elongation at break, % Example 1 2.98 8.19 18.30 720 Example 2 3.05 9.43 16.52 680 Example 3 3.68 9.38 14.76 650 Example 4 4.72 8.35 12.54 590 Comparative Example 1 3.23 10.68 26.20 650 Comparative Example 2 4.09 12.32 24.65 660

All samples were prepared to have a width of 18cm and a thickness of 12μm±2μm, and were subjected to film-laying degradation experiments under natural conditions. The degradation cycle and degradation performance were determined by measuring the percentage of mass loss.

The percentage of mass loss during degradation of some polyester thermoplastic elastomers is as follows:

Claims (10)

1. the mulching film resin with controllable biodegradation period is characterized in that polymerized monomers of the mulching film resin comprise:

a: one or more than two of aliphatic dibasic acid and anhydride, diester and diacid halide thereof are mixed;

b: unsaturated fatty acid and its polymer, acid anhydride, acyl halide or a mixture of two or more of them;

c: mixing aromatic diacid and one or more than two of anhydride, diester and diacid halide thereof;

d: one or more than two of aliphatic dihydric alcohol are mixed;

e: one or more than two of isocyanate, carbodiimide and epoxy compound chain extenders are mixed;

the mulching film resin is prepared by esterifying the polymerized monomer A, B, C and D under the condition of a catalyst, performing melt polycondensation or interfacial polymerization, and finally performing melt chain extension reaction.

2. The mulching film resin with the controllable biodegradation period according to claim 1, wherein the molar ratio of the sum of the functional groups of the polymerized monomer A, B, C to the functional groups of the polymerized monomer D is 1: 1-2; the molar ratio of the polymerized monomer C to the total polymerized monomer A, B, C is below 60%, and the addition amount of the chain extender E is below 10% of the total polymerized monomer by mass percent.

3. The mulching film resin with the controllable biodegradation period according to claim 1, wherein the number average molecular weight of the mulching film resin is 40000-70000 g/mol, and the molecular weight distribution is 1.5-3; the melt index of the mulching film resin is 3-5 g/10min, and the terminal carboxyl is 5-20 mol/t.

4. The mulching film resin with controllable biodegradation period according to claim 1, wherein the polymerized monomer A is one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, and anhydrides, diesters and dihalide derivatives thereof.

5. The mulch resin according to claim 1, wherein the polymeric monomer B is one or more of oleic acid, linoleic acid, linolenic acid, arachidonic acid, 20-C-5-enoic acid, 22-C-6-enoic acid and its polymer, anhydride, and acyl halide derivatives.

6. The mulch resin according to claim 1, wherein the polymeric monomer C is one or a mixture of two or more of terephthalic acid, phthalic acid, isophthalic acid, 1, 4-naphthalene dicarboxylic acid, 2, 6-naphthalene dicarboxylic acid, 2, 3-naphthalene dicarboxylic acid, 1, 8-naphthalene dicarboxylic acid and their anhydrides, diesters, and dihalide derivatives.

7. The mulching film resin with controllable biodegradation period according to claim 1, wherein the polymerized monomer D is ethylene glycol, 1, 3-propanediol, 1, 2-propanediol, 1, 4-butanediol, 1, 3-butanediol, 1, 2-butanediol, 2-methyl-1, 3-propanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, 2, 4-diethyl-1, 5-pentanediol, 2, 4-trimethyl-1, 3-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2-ethyl-1, 3-hexanediol, 1, 7-heptanediol, heptanediol, 1, 8-octanediol, 2-methyl-1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, polyoxyethylene, polyethylene glycol, and polypropylene glycol.

8. The mulch resin with controllable biodegradation period according to claim 1, wherein, the polymerization monomer E is one or a mixture of more than two of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, dicyclohexylcarbodiimide, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide, ethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, furan methyl glycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether and resorcinol diglycidyl ether.

9. A preparation method of mulching film resin with controllable biodegradation period is characterized by comprising the following steps:

(1) uniformly mixing the polymerized monomers A, B, C, D, adding 0.01-0.5% of catalyst by mass percent for esterification reaction, and completing the esterification stage when a collection system is not generated with water;

(2) then, performing polycondensation reaction, and finishing the polycondensation reaction when the melt index of the material is increased to 15-50 g/10 min;

(3) and (3) finally, carrying out chain extension reaction, and adding a polymerization monomer E after the step (2) to carry out melt chain extension reaction at the temperature of 150-230 ℃.

10. The preparation method of claim 9, wherein the esterification reaction temperature is 200-260 ℃ and the esterification reaction time is 1-3 h; the temperature of the polycondensation reaction is 230-250 ℃, the vacuum degree of the polycondensation reaction is 20-4000 pa, and the polycondensation reaction time is 2-5 h; carrying out a melt chain extension reaction at 150-230 ℃; the reaction catalyst in the step (1) is one or more of Lewis acid, germanium compounds, antimony compounds, titanium compounds, zinc compounds and tin compounds.