CN109970939A - Biomass thermoplastic polyurethane - Google Patents

Abstract

A kind of biomass thermoplastic polyurethane.The biomass thermoplastic polyurethane is formed by composition reaction, and the composition includes: the modified lignin resin of 1~50 parts by weight, wherein the hydroxyl value (OH value) of the modified lignin resin is less than 3mmol/g；First polyalcohol of 50~99 parts by weight, wherein the gross weight of the modified lignin resin and first polyalcohol is 100 parts by weight；And 40~60 parts by weight diisocyanate.

Description

Biomass thermoplastic polyurethane

technical field

The present invention specifically relates to a biomass thermoplastic polyurethane.

Background technique

Thermoplastic polyurethane (TPU) has been widely used in foam cushions, thermal insulation boards, electronic potting compounds, high-performance adhesives, surface coatings, packaging, surface sealants and synthetic fibers due to its flexibility and high elasticity.

The polyols used in thermoplastic polyurethane production are usually derived from petroleum products. However, due to environmental concerns, more and more industrial manufacturing methods are now attempting to replace petroleum products with biomass products. Among them, lignin, as a polyol biomass, can be easily extracted from food-grade and non-food-grade biomass, such as agricultural waste or forest biomass. However, the direct reaction of lignin and isocyanate to synthesize thermoplastic polyurethane will lead to the loss of thermoplasticity of the product due to excessive crosslinking.

Therefore, the industry needs a novel thermoplastic polyurethane that solves the problems encountered with known technologies.

SUMMARY OF THE INVENTION

In some embodiments of the present invention, the present invention provides a biomass thermoplastic polyurethane. The biomass thermoplastic polyurethane is formed by reacting a composition comprising: 1-50 parts by weight of modified lignin; 50-99 parts by weight of a first polyol; and 40-60 parts by weight parts of diisocyanate. Wherein, the hydroxyl value (OH value) of the modified lignin is less than 3 mmol/g, and the total weight of the modified lignin and the first polyol is 100 parts by weight.

Detailed ways

The embodiment of the present invention provides a biomass thermoplastic polyurethane. The present invention utilizes a specific proportion of modified lignin (OH value (OH value) less than 3 mmol/g), polyol and diisocyanate to prepare biomass thermoplastic polyurethane, so that the obtained biomass thermoplastic polyurethane has higher Mechanical strength and wear resistance. In addition, when adding unmodified lignin to react with polyols and diisocyanates, if the amount of lignin added is too large, it will easily lead to excessive crosslinking and loss of thermoplastic properties. If the amount of lignin added is insufficient, the mechanical strength and abrasion resistance of the obtained product cannot be significantly improved. Since the present invention uses modified lignin with a hydroxyl value (OH value) of less than 3 mmol/g to react with polyols and diisocyanates, excessive crosslinking will not be caused when the amount of lignin added is increased, so the obtained biomass polyurethane has a significantly improved High mechanical strength and wear resistance while maintaining thermoplasticity.

In some embodiments of the present invention, the present invention provides a biomass thermoplastic polyurethane. The biomass thermoplastic polyurethane is formed by reacting a composition, and the composition comprises: 1-50 parts by weight (for example, 2-25 parts by weight, 10-30 parts by weight or 10-20 parts by weight) of modified wood element; 50-99 parts by weight (for example, 75-98 parts by weight, 70-90 parts by weight, or 80-90 parts by weight) of the first polyol; and, 40-60 parts by weight (for example, 45-55 parts by weight) two Isocyanates. Wherein, the hydroxyl value (OH value) of the modified lignin is less than about 3 mmol/g, and the total weight of the modified lignin and the first polyol is 100 parts by weight.

In some embodiments of the present invention, the modified lignin may have lignin with at least end-capped functional groups, and the end-capped functional groups are bonded to residues obtained by dehydrogenation of hydroxyl groups on the lignin . Wherein, the end capping functional group (R ¹ ) is C _1-4 alkyl, phenyl, wherein R ² and R ³ are each independently C _1-4 alkyl; and, n is 1, 2, 3, or 4.

In some embodiments of the present invention, the C _1-4 alkyl group is a linear or branched chain alkyl group. For example, C _1-4 alkyl is methyl (methyl), ethyl (ethyl), propyl (propyl), isopropyl (isopropyl), n-butyl (n-butyl), tert-butyl (t-butyl) -butyl), sec-butyl (sec-butyl) or isobutyl (isobutyl).

In some embodiments of the present invention, the modified lignin of the present invention may have the structure of formula (I)

Wherein, L is the lignin residue left by removing i hydroxyl groups; R ¹ is C _1-4 alkyl, phenyl, wherein R ² and R ³ are each independently C _1-4 alkyl; and, n is 1, 2, 3, or 4; 3<i≤10 (eg: 3<i≤9, 3<i≤7, 3 <i≤6, 3<i≤5, 3<i≤4.8, 3<i≤4.6, 3<i≤4.4, 3<i≤4.2 or 3<i≤4.0).

In some embodiments of the present invention, the lignin used to form the modified lignin is sulfonate lignin, alkali lignin, or a combination thereof. In some embodiments of the present invention, the modified lignin has a hydroxyl value (OH value) of about 2-2.9 mmol/g, for example: 2.1-2.8 mmol/g, 2.2-2.7 mmol/g or 2.3-2.6 mmol/g. If the hydroxyl value (OH value) of the modified lignin is too high, it is easy to cause the PU crosslinking to lose its thermoplastic properties; if the hydroxyl value (OH value) of the modified lignin is too low, it is easy to lead to low molecular weight and poor physical properties.

In some embodiments of the present invention, the first polyol is a polymer polyol. In some embodiments of the present invention, the number average molecular weight of the first polyol is 500-100,000, such as 500-80,000, 1,000-60,000, 2,000-50,000 or 5,000-40,000.

In some embodiments of the present invention, the first polyol is a polyester polyol or a polyether polyol. In some embodiments of the present invention, the polyester polyol is poly(ethylene adipate) diol, poly(1,4-butanediol adipate) ) diol (poly(1,4-butylene adipate)diol), poly(ethylene dodecanoate)diol or poly(1,6-hexanediol adipate) ) diol (poly(1,6-hexathyleneadipate)diol).

In addition, in some embodiments of the present invention, the polyether polyol is polyethylene glycol (PEG), polypropylene glycol (PPG) or polytetramethylene ether glycol (polytetramethylene ether glycol, PTMEG).

In some embodiments of the present invention, the compositions of the present invention further comprise a second polyol. Wherein, the second polyol is different from the first polyol.

In some embodiments of the present invention, the second polyol is a polyester polyol, a polyether polyol, or a C _2-14 polyol. For example, the second polyol is poly(ethyleneadipate)diol, poly(1,4-butanediol adipate)diol (1,4-butylene adipate)diol), poly(ethylene dodecanoate)diol, poly(1,6-hexanediol adipate)diol (poly(ethylene dodecanoate)diol) (1,6-hexathyleneadipate)diol), polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene ether glycol (PTMEG), ethylene glycol (ethylene glycol) 1,3-propylene glycol), 1,3-propylene glycol (1,3-propylene glycol), glycerol (glycerol), 1,4-butanediol (1,4-butylene glycol), 1,5-pentanediol (1, 5-pentylene glycol), neopentylene glycol (neo-pentylene glycol), 1,6-hexanediol (1,6-hexylene glycol), 1,7-heptylene glycol (1,7-heptylene glycol), 1 , 8-octylene glycol (1,8-octylene glycol), 1,9-nonylene glycol (1,9-nonylene glycol), decylene glycol (decylene glycol), undecane glycol (undecylene glycol), dodecylene glycol Dodecylene glycol, tetradecylene glycol, rosin-diol, isosorbide or 2,5-furandiol. In some embodiments of the present invention, the second polyol is a polyester polyol or a polyether polyol, and the number average molecular weight of the second polyol is 500-100,000, such as 500-80,000, 1,000-60,000 , 2000～50000 or 5000～40000.

In some embodiments of the present invention, the weight ratio of the second polyol to the first polyol is 0.1-0.5 (eg: 0.11, 0.13, 0.15, 0.2, 0.22, 0.25, 0.27 or 0.29) , so as to simultaneously improve the mechanical strength, abrasion resistance and hydrolysis resistance of the biomass thermoplastic polyurethane of the present invention.

In some embodiments of the present invention, the first polyol is a polyester polyol, the second polyol is a C _2-14 polyol (polyol); the first polyol is a polyol an ester polyol, the second polyol is a polyether polyol; the first polyol is a polyether polyol, and the second polyol is a C _2-14 polyol; or , the first polyol is a polyether polyol, and the second polyol is a polyester polyol.

In some embodiments of the present invention, the diisocyanate is hexamethylene diisocyanate (HexamethyleneDiisocyanate, HDI), methylenediphenyldiisocyanate (MDI), toluene diisocyanate (toluene diisocyanate) , TDI), isophorone diisocyanate (isophoronediisocyanate, IPDI), 1,5-naphthyl diisocyanate (1,5-naphthalenediisocyanate, NDI), p-phenylene diisocyanate (p-phenylene diisocyanate, PPDI) ) or a combination of the above.

In some embodiments of the present invention, the composition comprises two or more diisocyanates.

In some embodiments of the present invention, the modified lignin of the present invention can be prepared by the following steps. First, lignin is reacted with an alkali agent to obtain a mixture. Next, a capping agent is added to the mixture, and the modified lignin is obtained after the reaction.

It is worth noting that the present invention uses a specific alkaline agent, which can selectively remove the hydrogen on the aromatic hydroxyl group and retain the hydrogen on the OH on the aliphatic hydroxyl group. Therefore, the modified lignin of the present invention has more aromatic end-capping agent functional groups (capping agent functional groups substituted for hydrogen on aromatic hydroxyl groups) than aliphatic end-capping agent functional groups (capping agent functional groups substituted for aliphatic hydroxyl groups) the amount of hydrogen on it).

In some embodiments of the present invention, the alkali agent is sodium hydroxide, potassium hydroxide, cesium carbonate, potassium carbonate or a combination thereof. In some embodiments of the present invention, the capping agent is XR ¹ , wherein X is halogen, and R ¹ is C _1-4 alkyl, phenyl, wherein R ² and R ³ are each independently C _1-4 alkyl; and, n is 1, 2, 3, or 4.

In some embodiments of the present invention, the preparation method of the biomass thermoplastic polyurethane of the present invention comprises heating and reacting the above-mentioned composition, and aging. In some embodiments of the present invention, the composition of the present invention may further comprise 0.01-5 parts by weight of a catalyst, the catalyst is an organobismuth catalyst, an organotin catalyst or a quaternary ammonium catalyst, wherein the modified wood The total weight of the element and the first polyol is 100 parts by weight.

In order to make the above-mentioned and other purposes, features, and advantages of the present invention more obvious and easy to understand, the following specific examples are given and described in detail as follows:

Preparation of modified lignin

Preparation Example 1

100 parts by weight of lignin (lignin, Mw: 1000-1500, extracted from rice husks) was added to a reaction flask and dissolved in acetone. After fully stirring, 120 parts by weight of potassium carbonate (potassium carbonate) was added to the reaction flask at room temperature. Next, after stirring for 30 min, 140 parts by weight of methyl iodide was added to the reaction flask at room temperature, so that some of the hydroxyl groups in the lignin were converted into methoxy groups. After 72 hours of reaction, a large amount of water was added to the reaction flask to cause solid precipitation. After filtration and drying, modified lignin (1) was obtained. The hydroxyl groups remaining in the modified lignin (1) were calculated by nuclear magnetic resonance spectroscopy, and the results are shown in Table 1.

Preparation Example 2

According to the preparation method of the modified lignin (1) described in Preparation Example 1, except that the reaction time was shortened from 72h to 24h, the modified lignin (2) was obtained. The hydroxyl groups remaining in the modified lignin (2) were calculated by nuclear magnetic resonance spectroscopy, and the results are shown in Table 1.

Table 1

aliphatic hydroxyl Aromatic hydroxyl Total hydroxyl value lignin 4.0 2.0 6.0mmol/g Modified Lignin(1) 2.0 0.5 2.5mmol/g Modified Lignin(2) 2.4 0.9 3.3mmol/g

Biomass thermoplastic polyurethane

Example 1

10 parts by weight of modified lignin (1) and 90 parts by weight of polytetramethylene ether glycol (PTMEG) (manufactured and sold by Aldrich, number average molecular weight of 1000-2000) were put into a reaction flask. After warming to 80°C, water was removed in vacuo for one hour. After the reaction flask was filled with argon, 13.5 parts by weight of 1,4-butanediol (1,4-butanediol) and 1 part by weight of an organic bismuth catalyst (manufactured and sold by King Industries, Inc., product number K348 ) was added to the reaction flask. After stirring sufficiently, 46.68 parts by weight of isophorone diisocyanate (manufactured and sold by Bayer) was added to the reaction flask, and stirring was continued. When the temperature of the reaction flask rose to 90°C-100°C, the stirring was stopped, and the resultant was quickly poured into a mold, and the mold was placed in an 80°C oven. After baking for 16 hours, biomass thermoplastic polyurethane (1) was obtained.

Next, the biomass thermoplastic polyurethane (1) is dissolved in dimethyl acetamide, and is baked in a low-temperature oven to form a film (baking temperature is 60-80° C.). After cutting into test pieces, the 100% modulus (100% modulus), tensile strength (tensile strength) and tensile elongation (tensile elongation) were measured with a universal tensile machine according to ASTMD412. The results are shown in Table 2. .

Example 2

The preparation method of biomass thermoplastic polyurethane (1) described in Example 1 was carried out, except that the modified lignin (1) was increased from 10 parts by weight to 20 parts by weight, and the polytetramethylene ether glycol was changed from 90 parts by weight to 20 parts by weight. The parts by weight were reduced to 80 parts by weight to obtain biomass thermoplastic polyurethane (2). Next, the biomass thermoplastic polyurethane (2) is dissolved in dimethyl acetamide, and is baked in a low-temperature oven to form a film (baking temperature is 60-80° C.). After cutting into test pieces, the 100% modulus (100% modulus), tensile strength (tensilestrength) and tensile elongation (tensile elongation) were measured with a universal tensile machine according to ASTM D412. The results are shown in Table 2. .

Comparative Example 1

100 parts by weight of polytetramethylene ether glycol (PTMEG) (manufactured and sold by Aldrich, number average molecular weight of 1000-2000) was placed in a reaction flask. After warming to 80°C, water was removed in vacuo for 1 h. After the reaction flask was filled with argon, 13.5 parts by weight of 1,4-butanediol (1,4-butanediol) and 1 part by weight of an organic bismuth catalyst (manufactured and sold by King Industries, Inc., product number K348 ) was added to the reaction flask. After fully stirring, 46.68 parts by weight of isophorone diisocyanate (isophorone diisocyanate, manufactured and sold by Bayer) was added to the reaction flask, and stirring was continued. When the temperature of the reaction flask rose to 90°C-100°C, the stirring was stopped, and the resultant was quickly poured into a mold, and the mold was placed in an 80°C oven. After baking for 16 h, polyurethane (1) was obtained. Next, the polyurethane (1) is dissolved in dimethylacetamide, and is baked in a low-temperature oven to form a film (baking temperature is 60-80° C.). After cutting into test pieces, the 100% modulus (100% modulus), tensile strength (tensile strength) and tensile elongation (tensile elongation) were measured with a universal tensile machine according to ASTM D412. The results are shown in Table 2. Show.

Comparative Example 2

The preparation method of the biomass thermoplastic polyurethane (2) described in Example 2 was carried out, except that the modified lignin (1) was replaced by the modified lignin (2). Since the obtained product is cross-linked and hardened during the aging process (90°C-100°C), it has no thermoplasticity and cannot form a film.

Comparative Example 3:

The preparation method of biomass thermoplastic polyurethane (2) described in Example 2 was carried out, except that the modified lignin (1) was changed to unmodified lignin (lignin, Mw: 1000-1500, extracted from rice husk) (residual The hydroxyl value of 6.0 mmol/g) was substituted. Since the obtained product is cross-linked and hardened during the aging process (90°C-100°C), it has no thermoplasticity and cannot form a film.

Table 2

It can be seen from Table 2 that compared with Comparative Example 1, the addition of modified lignin (1) (residual hydroxyl value of 2.5 mmol/g) can greatly improve the 100% modulus and tensile strength of the obtained biomass thermoplastic polyurethane. Although the addition of modified lignin (1) resulted in a decrease in the tensile elongation of the resulting biomass thermoplastic polyurethane, it remained above 700%.

Wear resistance test

The polyurethane (1) obtained in Comparative Example 1 and the biomass thermoplastic polyurethane (2) obtained in Example 2 of the present invention were measured for abrasion loss according to DIN 53516, and the results are shown in Table 3.

table 3

Wear (mm³) Polyurethane (1) 86.1 Biomass Thermoplastic Polyurethane(2) 76.6

It can be seen from Table 3 that by adding the modified lignin of the present invention, the abrasion resistance of the obtained biomass thermoplastic polyurethane can be indeed improved.

Hydrolysis resistance test

The biomass thermoplastic polyurethane (2) obtained in Example 2 of the present invention was subjected to a 35-day hydrolysis resistance test (according to the ASTM D882 standard test method) at 80° C. and 95% RH, and the biomass thermoplastic polyurethane (2) was measured during the process. The 100% modulus change rate before and after the hydrolysis resistance test, the results are shown in Table 4. The 100% modulo rate of change is calculated as follows:

Table 4

100% Modulus rate of change Biomass Thermoplastic Polyurethane(2) ~0%

It can be seen from Table 4 that by adding the modified lignin of the present invention, the biomass thermoplastic polyurethane of the present invention has good weather resistance, and its mechanical properties will not deteriorate even in a high temperature and high humidity environment.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned specific embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (14)

1. A biomass thermoplastic polyurethane formed by the reaction of a composition comprising: 1-50 parts by weight of modified lignin, wherein the modified lignin has a hydroxyl value (OH value) of less than 3 mmol/g; 50-99 parts by weight of the first polyol, wherein the total weight of the modified lignin and the first polyol is 100 parts by weight; and 40-60 parts by weight of diisocyanate. 2 . The biomass thermoplastic polyurethane according to claim 1 , wherein the modified lignin is lignin having at least a capping functional group (R1), and the capping functional group (R1) is ^a The residues obtained by dehydrogenation of hydroxyl groups on the lignin are bonded, wherein the end capping functional group (R ¹ ) is C _1-4 alkyl, phenyl, wherein R ² and R ³ are each independently C _1-4 alkyl; wherein, n is 1, 2, 3 or 4. 3. The biomass thermoplastic polyurethane according to claim 2, wherein the lignin is sulfonate lignin, alkali lignin or a combination thereof. 4 . The biomass thermoplastic polyurethane according to claim 1 , wherein the modified lignin has a hydroxyl value (OH value) of 2 to 2.9 mmol/g. 5 . 5. The biomass thermoplastic polyurethane of claim 1, wherein the first polyol is a polymer polyol. 6. The biomass thermoplastic polyurethane of claim 5, wherein the first polyol is a polyester polyol or a polyether polyol. 7. The biomass thermoplastic polyurethane of claim 1, wherein the composition further comprises a second polyol, wherein the second polyol is different from the first polyol. 8. The biomass thermoplastic polyurethane of claim 7, wherein the second polyol is a polyester polyol, a polyether polyol, or a _C2-14 polyol. 9 . The biomass thermoplastic polyurethane according to claim 7 , wherein the weight ratio of the second polyol to the first polyol is 0.1˜0.5. 10 . 10. The biomass thermoplastic polyurethane of claim 7, wherein the first polyol is a polyester polyol, and the second polyol is a _C2-14 polyol. 11. The biomass thermoplastic polyurethane of claim 7, wherein the first polyol is a polyester polyol and the second polyol is a polyether polyol. 12. The biomass thermoplastic polyurethane of claim 7, wherein the first polyol is a polyether polyol and the second polyol is a _C2-14 polyol. 13. The biomass thermoplastic polyurethane of claim 7, wherein the first polyol is a polyether polyol and the second polyol is a polyester polyol. 14. The biomass thermoplastic polyurethane according to claim 1, wherein the diisocyanate is hexamethylene diisocyanate (HexamethyleneDiisocyanate, HDI), methylenediphenyldiisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), 1,5-naphthalenediisocyanate (NDI), p-phenylene diisocyanate Isocyanate (p-phenylene diisocyanate, PPDI) or a combination of the above.