JP2003096101A - Cellulose/starch derivative, process for preparation thereof, and biodegradable laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new cellulose/starch derivative and a process for the preparation thereof which use the cellulose/starch derived from the plant resources with no environmental loads as well as use a simple process, and which has the dissolvability in various solvents and the thermal physical properties together with biodegradability, and also such functionality as water/oil repellency and gas barrier properties, and to provide a laminate using it. SOLUTION: The cellulose/starch derivative of a polybasic carboxylic acid monoesterified-cellulose or -starch which is esterified with a polybasic carboxylic anhydride, is characterized in that the derivative has a structure grafted by a ring-opening addition reaction of a monoepoxy compound onto an introduced carboxy group.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to biodegradability, thermoplasticity and water repellency of cellulose and starch obtained from plant resources.
The present invention relates to a derivative having various functions such as oil repellency and gas barrier property, a method for producing the derivative, and a laminate using the derivative.

[0002]

2. Description of the Related Art In recent years, as society and industry have changed to environmental conservation type or environmental recycling type, attention has been shifted from synthetic polymer materials made from petroleum to natural resources such as paper. Since paper is recyclable, biodegradable, and has low combustion heat when incinerated, there is an increasing demand for paper containers in place of various synthetic resin containers. Also, many biodegradable plastics, which are polymers that are decomposed by microorganisms in the environment and can be made into compost, have been researched and developed.
Biodegradable plastics are microbial synthetic systems, chemical synthetic systems,
Classified into three natural polymer types, the former two mainly consist of aliphatic polyesters. Among them, polylactic acid using lactic acid as a raw material uses raw materials obtained from plant resources, Attention has been paid. However, it is well known that these biodegradable resins have physical problems, even if they are different from the conventional general-purpose resins, apart from the manufacturing cost. It can be said that the appearance of new biodegradable resins is also expected. On the other hand, as natural polymer-based biodegradable plastics, diacetylated cellulose, modified starch and the like are already known as biodegradable resins, but since these have a basic structure of sugar chains derived from plants, In terms of safety and safety, and because it has a high affinity with paper that has a low environmental impact, it can be said that it is suitable for compounding with paper products.

However, existing natural polymer-based biodegradable resins have problems that they have a low heat melting property and have a limited range of applications, that they are difficult to be laminated on a substrate and that the manufacturing method is complicated. I'm holding. In addition, there is little diversity in solvent solubility and thermal physical properties, which are problems of conventional biodegradable resins in general, and it can be said that there is still room for further development and improvement.

Further, in terms of various functional materials,
Most of the conventional products are synthetic polymer derived from petroleum, and only a few are natural polymer type. A simple method of natural polymer type as a functionalized material for paper whose demand will continue to grow in the future. It is expected that functionalization methods and functional materials will be needed.

[0005]

The problem to be solved by the present invention is to solve various solvent solubility and thermal physical properties by a simple method using cellulose or starch derived from environmentally unfriendly plant resources. Another object of the present invention is to provide a novel cellulose / starch derivative having both biodegradability and functionality such as water / oil repellency and gas barrier property, a method for producing the same, and a laminate using the same.

[0006]

The present invention has been made in view of the above problems, and the above objects are achieved by the following configurations. In the invention according to claim 1, in the polycarboxylic acid monoesterified cellulose or starch esterified with the polycarboxylic acid anhydride, the introduced carboxyl group is grafted by a ring-opening addition reaction of the monoepoxy compound. Cellulose characterized by
It is a starch derivative.

According to a second aspect of the present invention, in the polyvalent carboxylic acid monoesterified cellulose or starch esterified with the polycarboxylic acid anhydride, the introduced carboxyl group has a monoepoxy compound and a polyvalent carboxylic acid anhydride. It is a cellulose / starch derivative characterized in that the product is subjected to a ring-opening addition esterification reaction alternately and grafted.

The invention according to claim 3 is the above-mentioned cellulose /
3. The cellulose / starch derivative according to claim 1, wherein the starch derivative has a polyvalent carboxylic acid monoester group substitution degree (DS) of 0.1 to 3.0. .

According to the invention of claim 4, the degree of molecular substitution of the monoepoxy compound of the cellulose / starch derivative (M.
S. ) Is 0.1-10.
Or the cellulose / starch derivative according to any one of 2).

The invention according to claim 5 is characterized in that the polyvalent carboxylic anhydride is any one of aliphatic, aromatic, and alicyclic aliphatic, or a mixture thereof. The cellulose / starch derivative according to any one of to 4.

According to a sixth aspect of the present invention, the monoepoxy compound is a long chain alkyl group-containing glycidyl ether, polyethylene glycol ether-containing glycidyl ether, polyethylene glycol ester-containing glycidyl ether, polyester-containing glycidyl ether, N-glycidyl phthalimide, or the like. The cellulose / starch derivative according to any one of claims 1 to 5, which has a structure that is plastic.

The invention according to claim 7 is characterized in that the monoepoxy compound has a functional group such as a fluoroalkyl group, a silicone group, a vinyl group or an alkoxy metal group. The cellulosic / starch derivative described in Crab.

The invention according to claim 8 is a ring-opening addition reaction of a monoepoxy compound to a carboxyl group introduced in a polyvalent carboxylic acid monoesterified cellulose or starch esterified with a polycarboxylic acid anhydride,
Alternatively, an alternating ring-opening addition esterification reaction of the introduced carboxyl group with a monoepoxy compound and a polyvalent carboxylic acid anhydride is carried out in a solvent by simultaneous or continuous one-tank reaction to be produced. And a method for producing a cellulose / starch derivative.

In the invention according to claim 9, the simultaneous or continuous one-tank reaction is carried out in an aprotic basic polar solvent such as dimethylformamide or dimethylacetamide with a tertiary amine or an alkali metal salt. Cellulose according to claim 8, which is carried out under a basic catalyst.
It is a method for producing a starch derivative.

A tenth aspect of the present invention is a biodegradable laminate characterized in that the cellulose / starch derivative according to any of the first to seventh aspects is laminated on a biodegradable substrate.

The invention according to claim 11 is characterized in that the cellulose / starch derivative is laminated on the substrate having biodegradability so as to have a thickness of 1 μm to 50 μm. It is the body.

The invention according to claim 12 is characterized in that the cellulose / starch derivative is laminated on the biodegradable substrate at a coating amount of 1 g / m ² to 25 g / m ^2. Or a biodegradable laminate in any one of 11 above.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below.

The cellulose derivative according to the present invention may be an ordinary pulp raw material, and specifically, bleached or unbleached sulfurous acid pulp or kraft pulp, crushed wood pulp, blast pulp, dissolving pulp, or heat of softwood or hardwood. Mechanical pulp (TMP) or chemical thermomechanical pulp (CTM)
P) and the like may be used alone or in combination of two or more. Also, non-wood pulp may be used, such as hemp, cotton (linter), straw, bamboo, kenaf, baccas, cypress, esparto, mulberry, sanpei, ganpi, ramie, microorganism-produced cellulose, baronia cellulose, ascidian cellulose, and the like. Various powdered cellulose powders pulverized with a high-pressure homogenizer, a freeze pulverizer, a mill, or the like, or acid-hydrolyzed microcrystalline cellulose powders may be used. Then, a cellulose fiber obtained by amorphizing treatment, specifically, a regeneration treatment with a mercerized copper ethylenediamine solution using an aqueous sodium hydroxide solution, SO ₂ -DEM (diethylamine)-
The crystallinity may be partially or wholly lowered by regeneration amorphous treatment with a DMSO (dimethyl sulfoxide) solution.

[0020] Among them, the "dissolving pulp" in which the purity of α-cellulose is enhanced by acid treatment such as SP (sulfite pulp) method in the process of refining various pulp fibers is preferable. It is preferable to use brands that are suitable for commercialization and that are compatible with various derivatizations are commercially available from paper manufacturers. At the time of use, it is preferable to use a defibrated pulp sheet.

Further, commercially available microcrystalline cellulose powder such as Avicel is also preferable because the reaction rate with the polyvalent carboxylic acid anhydride according to the present invention is high, the reaction solution is uniformly transparent, and the viscosity of the reaction solution is low.

The raw materials for the starch derivative according to the present invention include cornstarch, waxy cornstarch, wheat starch, potato starch, tapioca starch, various common starches such as sweet potato starch, bamboo shoot starch, konjac starch, and lightly oxidized. Modified starches such as modified starches and acid-treated soluble starches may be used alone or in combination.

However, modified starch such as soluble starch has a drawback that the yield of the reaction product is low due to its low molecular weight.

Since these various starches have a higher solvent solubility than cellulose, the reaction rate is fast and the reaction solution is uniformly transparent. Among them, corn starch is preferable because it is inexpensive, easily available, and the viscosity of the reaction liquid is low.

The raw material of the cellulose / starch derivative of the present invention may be a mixture of a plurality of the above celluloses and starches.

Cellulose of the present invention / polycarboxylic acid monoesterified cellulose / precursor of starch derivative /
The polycarboxylic acid anhydride used for starch may be any of aliphatic, aromatic and alicyclic aliphatic, for example,
Dicarboxylic acid anhydrides such as succinic anhydride, alkyl succinic anhydride, glutaric anhydride, cyclohexanedicarboxylic acid anhydride, naphthalene dicarboxylic acid anhydride, phthalic acid anhydride, and the like, alkenyl succinic acid anhydride, maleic acid. A compound having an unsaturated bond such as an anhydride or itaconic anhydride may be used, but it is not used intentionally because a side reaction may occur.

The polycarboxylic acid anhydride referred to in the present invention is
In addition to the above-mentioned dicarboxylic acid anhydrides, those having one dicarboxylic acid anhydride structure and one free carboxyl group in one molecule, such as trimetic acid anhydride and methylcyclohexene tricarboxylic acid anhydride, 1, 2,
A compound having one dicarboxylic acid anhydride structure and two free carboxyl groups, such as 3,4-cyclohexanetetracarboxylic acid-1,2-anhydride, is basically shown, and one dicarboxylic acid anhydride structure is basically used. Only show what you have. This is because a compound having two dicarboxylic acid anhydride structures, such as pyrrolimet acid anhydride, is not preferable because crosslinking occurs between molecules of cellulose or starch to be reacted.

A known method can be applied to the monoesterification of polyvalent carboxylic acid in the present invention. For example, in a heterogeneous esterification reaction of dicarboxylic acid anhydride and cellulose using methanesulfonic acid as a solvent and a catalyst, or in an aprotic polar solvent such as dimethyl sulfoxide, N, N-dimethylformamide, or N, N-dimethylacetamide, A heterogeneous esterification reaction of dicarboxylic acid anhydride and cellulose using a tertiary amine such as pyridine or triethylamine as a catalyst is known. Then, the present inventors have newly found that these reactions can be applied to starch. In addition, N, N-dimethylacetamide and N-methyl-2-
It is also possible to carry out homogeneous esterification reaction of dicarboxylic acid anhydrides with tertiary amines or alkali metal salts as catalysts in the state of dissolution of cellulose in a solvent in which lithium chloride is mixed with pyrrolidone, etc. Although an acid anhydride is used as a reaction reagent, the present inventors have found that even if a free carboxyl group is present in the structure of the dicarboxylic acid anhydride, the reaction proceeds without any problem and that a variety of physical properties are obtained. I found that

The tertiary amine catalysts include trimethylamine, triethylamine, dimethylbenzylamine,
Triphenylamine, triethanolamine, pyridine, pyrimidine, pyrazine, pyridazine, N-methylpyrrolidine, N-methylpyrazole, N-methylpyrrole, N-methylpiperazine, N-methylmorpholine, N
-Methylimidazole, N, N-dimethylpiperazine,
Examples include triazine. Examples of alkali metal salt catalysts include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate,
Examples thereof include sodium hydrogen carbonate, potassium hydrogen carbonate lithium hydrogen carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate, sodium dihydrogen phosphate, and sodium borohydride. When polycarboxylic acid monoesterified cellulose / starch and monoepoxy are reacted simultaneously or continuously in a single tank, acetate and stearate react with free acetic acid or stearic acid and monoepoxy compound. Because it cannot be used. Among the above basic catalysts, tertiary amines are particularly preferable, and the higher basicity as seen from pKa (the logarithm of the reciprocal of the acid dissociation constant), the faster the reaction rate, and triethylamine is particularly preferable.

Among these reactions, even those which are heterogeneous reactions are dissolved in a solvent and converted into a homogeneous solution as the reaction progresses. In particular, starch, which has a higher solubility than cellulose, tends to form a homogeneous system, and the reaction solution becomes transparent, resulting in a faster reaction rate. Among celluloses, microcrystalline cellulose powder such as Avicel has the same tendency.

Among these reaction methods, lithium chloride /
In all heterogeneous reactions other than the homogeneous reaction method using a dimethylacetamide solvent, the required amount of solvent is about 10 times the amount of cellulose or starch raw material, and the reaction temperature is from room temperature to about 70 ° C. It is a mild reaction, and the reaction time may be from 5 minutes to a long time of about 4 hours. In particular, a reaction system using a tertiary amine as a catalyst in an aprotic polar solvent such as dimethyl sulfoxide, dimethylformamide, or dimethylacetamide is preferable because it can be easily performed with a small amount of a general-purpose solvent and a catalyst.

The degree of substitution (DS.ltoreq.3.0) of the polyvalent carboxylic acid monoester group substituted for the three hydroxyl groups of cellulose or starch is controlled for cellulose and starch respectively. Carboxylic acid anhydrides and solvents,
Although it naturally changes depending on the type of catalyst, the present inventors have found that by controlling the reaction time, D.I. S. It was found that the range up to 3.0 can be easily changed. For example, in the case of a dissolving pulp raw material, when phthalic anhydride is reacted in dimethylsulfoxide at 65 ° C. with triethylamine as a catalyst, D.I. S. = About 1.5 and D.I. S. Of about 3.0, and under the same conditions except that dimethylformamide was used as the solvent, D.I. S. = About 1.5 and D.I. with a reaction time of about 4 hours. S. = About 3.0
You can get At this time, as pretreatment, amines,
In particular, the reaction proceeds smoothly if the tertiary amines used for the catalyst are dipped in the cellulose or starch raw material in the same amount as the catalytic amount for 5 hours or more. It is known that amines for pretreatment are primary amines such as ethylenediamine,
Pretreatment was also performed with tertiary amines because they form hydrogen bonds with celluloses and remain after washing with tertiary amines before the reaction, which reacts with polycarboxylic acid anhydride and becomes an inhibitor. Is easier. Furthermore, the solvent and the tertiary amines used in the reaction can be dried more smoothly to allow the reaction to proceed smoothly, and the reaction under an atmosphere of an inert gas such as nitrogen or the side reaction such as coloring can be reduced as compared with the atmosphere. .

The reaction mechanism of polyvalent carboxylic acid monoesterification reaction using this tertiary amine as a catalyst is as follows. First, in the pretreatment stage, the tertiary amine is adsorbed by the ion enemy to the hydroxyl group of cellulose. The activated hydroxyl group nucleophilically attacks the carbonyl carbon in the polycarboxylic acid anhydride and the reaction proceeds, so the amount of tertiary amines added to the glucose residue of the cellulose used in the reaction It is possible to control the degree of substitution of the polyvalent carboxylic acid monoester group with the cellulose by controlling the reaction with the polycarboxylic acid anhydride as it is. That is, when a substitution degree of 1 is obtained, a tertiary amine in an equimolar amount to the glucose residue of the cellulose to be subjected to the reaction is used.
Almost twice the molar amount, with a substitution degree of 3 it is slightly higher than 3.5-4.
A double molar amount of a tertiary amine is charged in a pretreatment step and then reacted with the polyvalent carboxylic acid anhydride as it is to obtain a desired degree of substitution.

As a method for measuring the degree of substitution of the polyvalent carboxylic acid monoester group, the amount of the carboxyl group and the amount of the polyvalent carboxylic acid monoester group can be measured by titration as in the case of cellulose acetate phthalate in the pharmacopoeia. It is possible. By using this titration method, the amount of unreacted free acid and the amount of ester group can be quantified. Also, once saponified and back titrated with acid,
The number of intermolecular diester crosslinks can be determined. The present inventors confirmed by the titration method that intermolecular diester crosslinking hardly occurs under the above-mentioned mild reaction conditions.

The various polyvalent carboxylic acid monoesterified celluloses / starches synthesized (produced) as described above are once isolated and purified, and then dissolved in an aprotic polar solvent such as acetone or dioxane. Redissolve in acetonitrile or aprotic basic solvent such as dimethylformamide or dimethylacetamide, and add various monoepoxy compounds using tertiary amines as catalysts to cause ring-opening addition reaction. The cellulose / starch derivative of the present invention can be synthesized (produced) by adding both the compound and the polyvalent carboxylic acid anhydride and subjecting them to ring-opening addition reaction or alternate ring-opening addition esterification reaction. At this time, when the monoepoxy compound to be reacted is a polyethylene glycol-based glycidyl ether, it is soluble only in water and alcohols. Therefore, it is dissolved in alcohols, particularly isopropanol having low reactivity due to steric hindrance, and the above-mentioned polyvalent carboxylic acid is dissolved. It is better to add to the monoesterified cellulose / starch solution and react.

Furthermore, it should be noted that epoxy compounds and dimethyl sulfoxide react with each other when heated,
Dimethylsulfoxide cannot be used as a solvent.

As a method for isolating the reaction product, in the case of various polycarboxylic acid monoesterified cellulose / starch as a precursor, the reaction solution is allowed to precipitate / precipitate in weakly acidic water, or The reaction solution is dissolved in a weak alkaline aqueous solution having a buffering action, such as an aqueous solution of trisodium phosphate-acetone or an aqueous solution of sodium hydrogen carbonate, and then precipitated and precipitated in weakly acidic water for isolation, which facilitates purification. For this purpose, the unreacted polycarboxylic acid is washed away with hot water at about 70 ° C.

The method for isolating the cellulose / starch derivative of the present invention in which the above precursor is reacted with various monoepoxy compounds is also a feature of the present invention, but the solvent of the reaction product depends on the monoepoxy compound to be reacted. Since the solubility is diverse, precipitation and precipitation may be performed in a poor solvent for the product. For example, a reaction product of a glycidyl ether containing a polyethylene glycol ether soluble in water and an alcohol and the precursor may be precipitated or precipitated in acetone, or a glycidyl ether containing a water-insoluble long-chain alkyl group and the precursor may be precipitated. The reaction product of is isolated in water by precipitation and precipitation.
Purify.

The molecular weight substitution degree (MS) of various monoepoxy compounds is calculated by the following equation.

M. S. = {(Weight of raw material monoepoxy compound-weight of unreacted monoepoxy compound) / molecular weight of monoepoxy compound} / (weight of charged cellulose or starch / molecular weight of cellulose or starch)

This degree of molecular substitution is such that the degree of substitution (DS) of the polyvalent carboxylic acid monoester group of the precursor polyvalent carboxylic acid monoesterified cellulose / starch is 0.1.
On the other hand, in the case of ring-opening addition reaction of various monoepoxy compounds alone, the same M.S. S. = 0.1 to 3.0, and it is not always necessary to subject the polyvalent carboxylic acid monoester group of the precursor to a 100% monoepoxy compound for ring-opening addition reaction. Thereby, the cellulose of the present invention /
The range of various physical properties of starch derivatives has become wide. Further, in the case of the alternating ring-opening addition esterification reaction between various monoepoxy compounds and polyvalent carboxylic acid anhydrides, the monoepoxy compound is targeted in the range of 0.1 to 10, and M.P.
S. If ≧ 10 or more, the reaction is difficult.

As the monoepoxy compound to be reacted,
It can be selected depending on the functionality imparted to cellulose or starch. For example, when it is desired to impart thermoplasticity, polyethylene glycol ether-containing glycidyl ether or polyethylene glycol ester-containing glycidyl ether, long-chain alkyl group-containing glycidyl ether, polyester-containing glycidyl ether, N-glycidyl phthalimide, etc. Lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether, phenol (ethylene oxide) ₅ glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, p-tert-butylphenyl ether, C11-
C15 alcohol glycidyl ether and the like are commercially available, and a long-chain alkylene oxide starting from the simplest ethylene oxide to propylene oxide may be used. In addition, aliphatic glycidyl ether containing aliphatic polyester synthesized from aliphatic polyester glycol and epichlorohydrin, and glycidyl ether containing aliphatic polyester obtained by reacting glycitol with cyclic ester such as ε-caprolactone are considered.

Further, since ethylene glycol, which is a raw material of polyethylene glycol-based glycidyl ethers, is an ethanol derivative obtained by fermentation of glucose, which is a plant resource, it can be said that it is a material that does not give any load to the environment.

In the cellulose / starch derivative of the present invention having the above-mentioned thermoplastic monoepoxide compound as a side chain, the basic structure is a sugar chain, and the side chain monoepoxy compound is a polyvalent carboxylic acid. Since it is bound to the sugar chain through an ester bond via the, the site is hydrolyzed or microbially decomposed to have a low molecular weight, and thus biodegradability can be imparted. In addition, it has the advantage that various thermal physical properties and solvent solubility of various monoepoxy compounds can be imparted to cellulose and starch, which is considered to supplement the point that has been a problem of conventional biodegradable resins in general. . Therefore, it can be used on a paper substrate or other biodegradable resin substrate for sealant application by coating or melt extrusion molding, heat sealing application, and the like. Further, since the basic structure is a sugar chain, the use of a paper base material having the same basic structure has a strong affinity for the paper base material and is more effective.

When it is desired to impart water repellency and oil repellency, the monoepoxy compound may be a monoepoxy compound containing silicone groups of various molecular weights or 3- (1H, 1H, 9H-hexadecafluorononyloxy) -1,2. -Epoxypropane, 3-perfluorooctyl-1,2-epoxypropane, and other perfluoroepoxyalkanes are commercially available, and these may be reacted. Since these also have a high affinity with paper, it is considered that they can be used as water-repellent paper, oil-repellent paper, release paper, etc., as a mixed paper material at the time of paper making and a coating agent for paper.

In addition, an active vinyl bond can be introduced by reacting with allyl glycidyl ether or glycidyl methacrylate, and as the epoxy group-containing organic metal alkoxide, (3-glycidoxypropyl) trimethoxysilane or 2- ( An alkoxysilyl group can be introduced by reacting with an epoxy group-containing silane coupling agent such as 3,4-epoxycyclohexyl) ethyltrimethoxysilane. These can also be used as a coating agent for paper, and it is considered that gas barrier properties can be imparted by hydrolyzing the alkoxysilyl group.

In the case where the cellulose / starch derivative of the present invention is produced by simultaneous or continuous one-tank reaction of monoesterification reaction of polyvalent carboxylic acid of cellulose or starch and ring-opening addition reaction of various monoepoxy compounds, Since dimethylsulfoxide as a solvent reacts with epoxies when heated as described above, tertiary amines are used as catalysts in other aprotic polar solvents such as dimethylformamide and dimethylacetamide, and By charging both anhydride and various monoepoxy compounds, polyvalent carboxylic acid monoesterification and epoxy ring-opening addition reaction to the carboxyl group introduced by the reaction, or alternate ring-opening addition esterification reaction occur simultaneously. Or, after the monoesterification reaction with polyvalent carboxylic acid anhydride, continuously in the reaction solution The added ring-opening addition reaction type monoepoxy compound, or any method of continuously causing alternating ring-opening addition esterification reaction also added polycarboxylic acid anhydrides are also possible. At this time, the reaction between the carboxyl group introduced into the cellulose or starch and the epoxy is catalyzed by a tertiary amine, and therefore the epoxy undergoes β-cleavage to add. Further, the same operation procedure is used when methanesulfonic acid is used as a solvent and a catalyst, and in this case, since it is an acid catalyst, there are literatures in which epoxy is generally only α-cleavage, but β-cleavage It is thought that both are added and caused.

Examples of the biodegradable substrate include paper. The method for producing a biodegradable laminate in which the cellulose / starch derivative of the present invention is laminated includes dissolving the cellulose / starch derivative of the present invention in water or various organic solvents and coating it on paper or various biodegradable resin films. Good. As a coating method, a conventional method can be applied, and a roll-shaped material can be laminated by a winding method by a coating device. In the case of paper, it may be coated on one side or both sides of the paper with a size press device, a gate roll device or the like in the drying zone of the paper machine. Further, since the cellulose / starch derivative of the present invention is thermoplastic, it can be melted and extruded. By selecting a monoepoxy compound as a side chain, not only can the cellulose / starch derivative be given various functionalities such as water repellency and gas barrier properties, but it can also be used as a biodegradable substrate such as paper. By stacking, high functionality can be added without impairing the biodegradability of the base material.

In the case of melt extrusion molding, the coating amount is 1 to 50 μm on the substrate, and in the case of a coating solution dissolved in a solvent, the coating amount is 1 to 25 g / m ² in absolute dry amount. If it is less than that, the sufficient effect expected by the present invention cannot be obtained, and if it is more than that, the effect is saturated and it is not economical. The biodegradable laminate thus obtained can be used in various fields such as various packaging materials and disposable containers.

[0050]

EXAMPLES Next, the present invention will be described more specifically based on Examples and Comparative Examples, but these do not limit the present invention.

<Example 1> Dissolved pulp (NSP-P, manufactured by Nippon Paper Industries Co., Ltd.) was put in a reaction vessel in an absolute dry amount of 1 g (6.17 mmol in terms of glucose), and 1.87 g of dry triethylamine ( 24.68 mmol) and add 1
Pre-treatment was carried out by immersing in the evening. In addition, phthalic anhydride 4.
10 g of dry dimethylsulfoxide in which 57 g (30.85 mmol) was dissolved was added, and the reaction was carried out at 65 ° C. for about 40 minutes with stirring. A mixed solution of 15 g of acetone, 15 g of water, and 15 g of a 10 wt% trisodium phosphate aqueous solution was added to the resulting orange-colored uniform viscous solution to dissolve, and 5 wt
When poured into 300 g of a sulfuric acid aqueous solution with stirring, a white solid was deposited. It was filtered, and the filtered product was thoroughly washed and filtered with hot water of about 70 ° C. The yield of well dried white solid was about 3.02 g. When analyzed by 1 H-, 13 C-NMR and IR, it was found to be a cellulose derivative into which phthalic acid was introduced, and D.I. S. = About 2.5 phthalic acid monoesterified cellulose was found.

Next, 3 g (5.64 mmol) of this phthalic acid monoesterified cellulose was dissolved in 10 g of dry dimethylformamide, and lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether (Nagase Kasei Co., Ltd.) was added.
Manufactured by Denacol EX-171, m.p. p. = Approx. 40 ° C) 1
2 g (from epoxy equivalent 971 epoxy group mol = 1
2.36 mmol) and 2.49 g of triethylamine (4
What was melt | dissolved in the isopyr alcohol 10g was added, and it was made to stir and react at 70 degreeC for about 30 minutes. When 20 g of acetone was added to the reaction solution, a white solid was deposited, which was filtered and washed. The dry yield of the white solid was about 13 g, which was 1H-, 13C-NMR and I.
When analyzed by R, it was found to be cellulose phthalate having ring-opened addition of lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether. The liquid broth was analyzed by gas chromatography and the amount of unreacted monoepoxy compound was quantified. S. Was 2.08. The product was well soluble in water and alcohols, and when its melting point was examined by differential scanning calorimetry (hereinafter referred to as DSC), a sharp melting peak appeared at around 55 ° C. The cellulose derivative thus obtained is dissolved in water, and a 10 wt% solid content aqueous solution is applied to a cup base paper (basis weight: 3 by a wire bar coating method).
20 g / m ² ) so that the coating has an absolute dry weight of 5 g / m ² , and is dried by heating to obtain a biodegradable laminate.

Example 2 Cellulose phthalate obtained by ring-opening addition of lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether, which is the cellulose derivative obtained in Example 1, was extruded at a temperature of 200 ° C. by a T-die type melt extrusion molding machine. And cup base paper (basis weight: 320 g / m
² ) A biodegradable laminate was obtained by coating the above with a thickness of 30 μm.

<Example 3> Dissolved pulp (NSP-P manufactured by Nippon Paper Industries Co., Ltd.) was put in a reaction vessel at an absolute dry amount of 1 g (6.17 mmol in terms of glucose), and 2.49 g of dry triethylamine ( 4 × 6.17 mmol) was added and the mixture was immersed overnight for pretreatment. Then, 15 g of dry dimethylformamide in which 4.57 g (30.85 mmol) of phthalic anhydride was dissolved was added, and the mixture was stirred at 65 ° C. for about 4 hours. Lauryl alcohol (ethylene oxide) was continuously added to the orange-colored uniform viscous solution.
12 g of ₁₅ glycidyl ether (Denacol EX-171 manufactured by Nagase Kasei Co., Ltd., epoxy group mol = 12.36 mmol from epoxy equivalent 971) dissolved in 10 g of isopyr alcohol was added, and the mixture was added at 65 ° C. to about 3
The reaction was stirred for 0 minutes. 20 g of acetone in the reaction solution
Upon addition, a white solid precipitated, which was filtered and washed.
The dry yield of the white solid was about 14 g, which was analyzed by 1H-, 13C-NMR and IR in the same manner as in Example 1 to find that it was cellulose phthalate to which lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether was ring-opened and added. all right. The monoepoxy compound M.V. determined in the same manner as in Example 1 was used. S. Was 1.71. The product dissolves well in water and alcohols, and its melting point was examined by DSC.
Similar to Example 1, a sharp melting peak appeared at around 55 ° C.

Example 4 Corn starch (produced by Kanto Kagaku Co., Ltd.) in an absolute dry amount of 1 g (6.
(17 mmol) was placed in a reaction vessel, 1.87 g (3 × 6.17 mmol) of dry triethylamine was added, and the mixture was immersed overnight for pretreatment. In addition, 4.57 g of phthalic anhydride
15 g of dry dimethylformamide in which (30.85 mmol) was dissolved was added, the mixture was stirred at 65 ° C. for about 3 hours, and the same operation as in Example 2 was performed. The product was a white solid in a dry yield of about 13 g and was analyzed by 1 H-, 13 C-NMR, and IR, and was found to be phthalate starch to which lauryl alcohol (ethylene oxide) ₁₅ glycidyl ether was ring-opened. The monoepoxy compound M.V. determined in the same manner as in Example 1 was used. S. Was 1.55.
The product dissolves well in water and alcohols.
When the melting point was examined by SC, a sharp melting peak appeared at around 55 ° C. as in Example 1.

Example 5 Disintegrated dissolving pulp (NSP-P manufactured by Nippon Paper Industries Co., Ltd.) was put in a reaction vessel at an absolute dry amount of 1 g (6.17 mmol in terms of cellulose), and 2.49 g of dry triethylamine ( 4 × 6.17 mmol) was added and the mixture was immersed overnight for pretreatment. To this, 15 g of dry dimethylformamide in which 4.57 g (30.85 mmol) of phthalic anhydride was dissolved was added, and the mixture was stirred at 65 ° C. for about 3 hours. N-glycidyl phthalimide (manufactured by Nagase Kasei Co., Ltd., Denacol EX-731, mp = 94-) was continuously added to the resulting orange uniform viscous solution.
96 ° C) 2.67 g (epoxy group mol = 12.36 mmol based on epoxy equivalent 216) was directly added,
The reaction was carried out under stirring for about 30 minutes. The reaction solution is treated with water 300
When poured into ml, a white solid was deposited, which was filtered and washed. The dry yield of the white solid was 6 g, 1H-, 13C.
-By NMR and IR analysis, it was found that N-glycidyl phthalimide was a cellulose phthalate having a ring-opening addition. The monoepoxy compound M.V. determined in the same manner as in Example 1 was used. S. Was 1.7. The product was well soluble in general-purpose solvents such as methyl ethyl ketone, dioxane, and ethyl acetate. When the melting point was examined by DSC, a sharp melting peak appeared at around 100 ° C.

<Comparative Example 1> The melting point of commercially available diacetylated cellulose (acetyl group substitution degree DS = 2.85) was determined to be DS.
When examined by C, there was only a broad peak (softening point) around 230 ° C.

Test Example 1 Next, 1.0 g of the powdery cellulose / starch derivative samples of Examples 3 to 5 and Comparative Example 1 were put into a pellet molding machine and compressed (20 tf-
After 5 minutes), pellets (Φ = 40 mm) were prepared. The pellets and the laminates of Examples 1 and 2 were mixed with pig dung and sawdust to adjust the water content to about 65% and embedded in the compost that had been stored for about one month, and the biodegradability was evaluated. After about 4 months, all of the examples of the present invention were disassembled into pieces and did not stop the original shape. On the other hand, the pellets of the diacetylated cellulose of Comparative Example 1 were decomposed only slightly.

[0059]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to obtain a variety of thermal properties which are not sufficient for conventional biodegradable resins by a simple method for producing cellulose and starch obtained from plant resources having a low environmental load. It is possible to obtain a novel cellulose / starch derivative that complements physical properties and solvent solubility and has biodegradability. That is, its versatility is based on the idea of appropriately selecting the monoepoxy compounds to be reacted, and it is used as a sealant on paper base materials or other biodegradable resin base materials by a coating method or melt extrusion molding. It can be effectively used as a heat seal application. Further, when a paper base material is used, it has high affinity with the cellulose / starch derivative of the present invention having a basic structure of a sugar chain and firmly adheres to it, and can be used more effectively. Further, as other functions, for example, a novel cellulose / starch derivative having functionality such as water / oil repellency and gas barrier property and a method for producing the same are enabled, and water repellent paper, oil repellent paper, release paper, gas barrier paper, etc. It can be used for functional paper applications.

Continued front page    (72) Inventor Tomoko Kato             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. F-term (reference) 4C090 AA02 AA03 BA15 BA25 BA65                       BB84 BB97 BD04 BD17 BD25                       BD36 CA38 DA28 DA31                 4F100 AJ04A AJ07A AL04A AT00B                       BA02 DG02 DG10B EH46A                       GB16 GB90 JB06 JB08 JB20B                       JC00B JD02 JL02 JL08A                       YY00A

Claims (12)

[Claims] 1. A polyvalent carboxylic acid monoesterified cellulose or starch esterified with a polycarboxylic acid anhydride, wherein the introduced carboxyl group is grafted by a ring-opening addition reaction of a monoepoxy compound. Characterized cellulose / starch derivatives. 2. In a polyvalent carboxylic acid monoesterified cellulose or starch esterified with a polyvalent carboxylic acid anhydride, the introduced carboxyl groups are alternately ring-opened with a monoepoxy compound and a polyvalent carboxylic acid anhydride. A cellulose / starch derivative characterized by being subjected to an addition esterification reaction and being grafted. 3. The polycarboxylic acid monoester group substitution degree (DS) of the cellulose / starch derivative is 0.1 to 0.1.
The cellulose / starch derivative according to claim 1, wherein the cellulose / starch derivative is 3.0. 4. The cellulose / starch according to claim 1, wherein the monoepoxy compound of the cellulose / starch derivative has a degree of molecular substitution (MS) of 0.1 to 10. Derivative. 5. The polyvalent carboxylic anhydride is any one of aliphatic, aromatic, alicyclic aliphatic, or a mixture of a plurality thereof, in any one of claims 1 to 4. The described cellulose / starch derivative. 6. The monoepoxy compound has a thermoplastic structure such as long-chain alkyl group-containing glycidyl ether, polyethylene glycol ether-containing glycidyl ether, polyethylene glycol ester-containing glycidyl ether, polyester-containing glycidyl ether, and N-glycidyl phthalimide. Claim 1 characterized by the above.
The cellulose / starch derivative according to any one of 1 to 5. 7. The monoepoxy compound has a functional group such as a fluoroalkyl group, a silicone group, a vinyl group, or an alkoxy metal group.
7. The cellulose / starch derivative according to any of 6. 8. A ring-opening addition reaction of a monoepoxy compound to an introduced carboxyl group in a polyvalent carboxylic acid monoesterified cellulose or starch esterified with a polyvalent carboxylic anhydride, or an introduced carboxyl group. Cellulose characterized by being produced by alternating ring-opening addition esterification reaction of monoepoxy compound and polyvalent carboxylic acid anhydride into a solvent by simultaneous or continuous one-tank reaction in a solvent. Method for producing starch derivative. 9. The simultaneous or continuous one tank reaction,
9. Production of a cellulose / starch derivative according to claim 8, which is carried out in an aprotic basic polar solvent such as dimethylformamide or dimethylacetamide under a basic catalyst such as a tertiary amine or an alkali metal salt. Method. 10. A biodegradable laminate comprising the cellulose / starch derivative according to claim 1 laminated on a biodegradable substrate. 11. The biodegradable laminate according to claim 10, wherein the cellulose / starch derivative is laminated on the biodegradable substrate in a thickness of 1 μm to 50 μm. 12. The coating amount of the cellulose / starch derivative to the biodegradable substrate is 1 g / m ² to 25 g.
/ M ² laminated to each other, characterized in that
1. A biodegradable laminate for any one of 1.