JP3477503B2 - Lignocellulose-liquefied starch solution and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied solution having a high biomass concentration containing lignocellulose and starch, and a method for producing the same. More specifically, lignocellulose-starch liquefied solution useful for various resin raw materials having a high biomass concentration and a low combustion calorific value, biodegradability or biodegradability, and liquefying lignocellulose such as wood and the like, and its production. It is about law.

The lignocellulose-starch liquefied solution is expected to be used as a resin raw material in a wide variety of fields such as adhesives, molding materials, foams, paints and fillers.

The term "biomass" means the amount of organisms (body), and a substance having a high biomass concentration generally has a low combustion calorific value and is superior in biodegradability and biodegradability.

[0004]

2. Description of the Related Art As a part of effective utilization of wood materials, waste materials, waste paper, etc., which have low utility value, they are liquefied in the presence of an acid catalyst and polyhydric alcohol to form a solution, and the liquefied lignocellulose solution is obtained. It has already been proposed to use it as various resin raw materials.

A liquefaction method is disclosed in, for example, Japanese Patent Laid-Open No. 4-10
Although known from Japanese Patent No. 6128, there is a problem that the concentration that can bring the lignocellulosic substance into a liquid state is not necessarily high during liquefaction. Conventionally, when a liquefaction solution is prepared by dissolving a lignocellulosic substance in a polyhydric alcohol in the presence of an acid catalyst, it is generally considered that the residue cannot be effectively utilized when the residue ratio exceeds 20%, and liquefaction is caused. The charge concentration of the lignocellulosic material that is sufficiently advanced is 35%
The degree has been limited. That is, even if the concentration of the raw material lignocellulosic material is increased, the liquefaction concentration is limited, and even if the lignocellulosic material which is the raw material is added more than necessary, the residue will increase. Therefore, in order to reduce the residue and efficiently liquefy it industrially, the raw material concentration should be 35%.
I had no choice but to make it less than%.

However, even if the raw material lignocellulosic substance is liquefied at a low concentration so that the raw material lignocellulosic substance can be almost liquefied, the concentration of the liquefied product inevitably becomes low, and such a low liquefied substance is obtained. Low combustion calorific value at concentration,
There was a problem that the characteristics of biodegradability and biodegradability could not be fully exploited. Further, if the liquefaction product having a low concentration is concentrated, the viscosity increases and it cannot be handled as a liquid, which causes a practical problem.

[0007]

A so-called high biomass concentration resin material having characteristics such as low combustion calorific value and biodegradability is one of the recent demands as an environment-friendly material. When considering lignocellulose liquefaction as its raw material, it is preferable that the concentration of liquefied lignocellulose is high, but the concentration of liquefiable lignocellulose is 35
In some cases, about% is not enough. If the concentration of the lignocellulosic liquefaction is increased, various problems occur as described above.

It is possible to use starch instead of the lignocellulosic material, but using starch as a raw material is not desirable from the viewpoint of cost effective and efficient use of resources. Furthermore, since starch has a lower molecular weight than lignocellulosic substances, there is a problem that the range of utilization of the liquefied solution is restricted.

Therefore, the problem to be solved by the present invention is to provide a method for producing a liquefied lignocellulose solution having a high biomass concentration without the above-mentioned problems.

The lignocellulosic liquefied solution referred to in the present invention means not only the lignocellulosic material completely liquefied, but also the lignocellulosic material having a residual rate of less than 20% of the input amount.

[0011]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve such conventional problems. As a result, a lignocellulosic material such as wood is heated in the presence of an acid catalyst and a polyhydric alcohol. Then, after the liquefaction of the lignocellulosic material progressed, it was found that a liquefied solution with a high biomass concentration was obtained by adding starch and continuing heating, and completed the present invention.

[0012]

The most important feature of the present invention is the conventional method of liquefying a lignocellulosic material by heating the lignocellulosic material in the presence of an acid catalyst and a polyhydric alcohol.
After the lignocellulosic substance has substantially started to liquefy, starch is added and heating is continued while recondensation of the liquefied lignocellulosic substance does not proceed.

By adding the starch in this way, the starch itself is liquefied together with the lignocellulosic material,
As a result, a liquefied solution with a high biomass concentration containing a high concentration of lignocellulosic material and starch can be obtained.

At this time, if the starch is added together with the lignocellulosic material from the beginning, the biomass concentration is improved, but the liquefaction of the lignocellulosic material is rather decreased, and the lignocellulosic material once liquefied is added after the start of recondensation. Then, although the biomass concentration may be slightly improved, the recondensation of the lignocellulosic material proceeds and the residue increases.

Particularly importantly, in the case of conventional liquefaction of a lignocellulosic substance alone, liquefaction did not proceed sufficiently when a high-concentration raw material solution was used, but when liquefying by adding starch as in the present invention, This means that the liquefaction of the lignocellulosic material does not decrease even with a high-concentration raw material solution.

The lignocellulosic material used as one of the starting materials in the present invention is wood powder, wood fiber, crushed wood such as wood chips and veneer, plant fiber such as straw and chaff, ground pulp. , Thermomechanical pulp, various types of pulp such as waste paper, and any of those that have been used in the field of this kind are used, for example, those described in JP-A-4-106128. Etc. can all be used in the present invention.

At this time, various kinds of wood are widely included, and typical examples thereof include mackerel, sitka spruce, cedar, red pine, poplar, lauan and the like.

The lignocellulosic material may be subjected to a pretreatment with, for example, a halogen, and examples thereof include those described in JP-A-63-17961.

As the starch used as another starting material in the present invention, a wide variety of ordinary starches such as corn starch, potato starch, tapioca starch and wheat starch can be used. Furthermore, processed starch, for example, esterified, etherified, oxidized, enzymatically decomposed, etc. is also used. The degree of substitution of esterified and etherified starch is 0.
01 to 0.5 is preferable, and other crosslinked starch can also be used. The degree of substitution here is the average value of the substituted hydroxyl groups per glucose residue of the starch derivative. The degree of crosslinking is usually a degree of substitution of 0.0003 to 0.01. As the oxidized starch, the degree of substitution of the carboxyl group is 0.00001 to 0.02.
It is preferably produced to some extent, and the enzymatic degradation product of starch refers to a product obtained by degrading starch with an enzyme such as α-amylase, β-amylase, glucoamylase, isoamylase, α-glucosidase, and prunase. Further, by-products generated during starch production are also included. Of these, raw starch is the best.

The polyhydric alcohol used in the present invention is a dihydric or higher alcohol, such as an aliphatic polyhydric alcohol,
Examples thereof include polyether polyols and polyester polyols. Especially polyethylene glycol,
Glycerin, ethylene glycol, polycaprolactone and the like are preferable. Each of the polyhydric alcohols may be used alone, or two or more thereof may be appropriately mixed and used. A polyhydric alcohol having a relatively large molecular weight and a polyhydric alcohol having a relatively small molecular weight are used in combination. Is preferred.

For the purpose of further lowering the viscosity of the solution or facilitating the liquefaction / dissolution, water or one or more organic solvents such as monohydric alcohol, acetone, ethyl acetate or the like from the beginning or during the liquefaction / dissolution. It is also possible to add and coexist. These organic solvents are usually added in an amount of preferably 1 to 10 parts by weight based on 100 parts by weight of the polyhydric alcohol.

In the present invention, the liquefaction reaction is carried out at normal pressure in the presence of an acid catalyst. The acid catalyst may be a mineral acid, an organic acid, or a Lewis acid, and preferable examples thereof include sulfuric acid, toluenesulfonic acid, phenolsulfonic acid, aluminum chloride, zinc chloride and boron trifluoride. The amount of the acid catalyst added is 0.1 to 10% by weight, preferably 0.5 to 5% by weight. Reaction temperature is 100 ~
200 ° C., preferably 120 to 180 ° C., and appropriately selected from them.

It is preferable to appropriately stir during the liquefaction reaction. By this stirring, torque can be applied to the suspension to enhance the efficiency of liquefaction and dissolution.

The liquefaction reaction comprises a first stage liquefaction in which lignocellulose such as wood is heated and liquefied in the presence of an acid catalyst and a polyhydric alcohol, and subsequently a second stage liquefaction in which starch is added and heating is continued.

The heating time of the first stage varies depending on the concentration of the lignocellulosic substance, but the point is that after the liquefaction of the substance is started, preferably 80% of the lignocellulose to be finally liquefied is liquefied. It is a period during which recondensation of the liquefaction does not proceed from the time, and is usually about 40 to 90 minutes.

The amount of starch added in the second stage reaction is 30 to 250%, preferably 80 to 150%, based on the lignocellulose.

In this second stage reaction, the starch is sufficiently liquefied,
In addition, it is usually about 10 to 80 minutes while the condensation of the liquefied lignocellulosic material and starch does not proceed.

At this time, the total of the liquefaction time of the first stage and that of the second stage must be within a range such that the liquefaction rate does not decrease again due to recondensation of the liquefied components in the liquefaction reaction liquid. There is. Usually, the heating temperature is the same between the first stage liquefaction and the second stage liquefaction, but different temperatures may be used. Also, usually the second
Polyhydric alcohols, acid catalysts and other additives are not added during the stage liquefaction, but these may be further added if necessary.

The concentration of the solution obtained by liquefying the lignocellulosic material and starch thus obtained varies depending on the purpose of use of the solution, but is in the range of 35 to 75% by weight.

The apparatus for liquefaction may be any apparatus that can carry out this reaction, and is equipped with an inner wall having high acid resistance and a reflux apparatus, preferably a concentrating apparatus such as vacuum distillation. Liquefied liquefaction is achieved by using a device that allows the entire reaction system to mix well in the initial stage and sufficient agitation in the latter period, or a device that allows such mixing and stirring to be performed efficiently throughout the reaction period. It is desirable because it can promote dissolution.

The liquefied solution obtained in the present invention is a liquefied solution containing a lignocellulosic material and starch, and a polyhydric alcohol and an acid catalyst. The total concentration of the liquefied lignocellulosic material and starch is about 35 to 75% by weight, and the biomass concentration is extremely high. More specifically, lignocellulosic material 10 to 30%, starch liquefaction 5
~ 65%, polyhydric alcohol 65-25% and acid catalyst 0.
It is 25 to 6.5%. In some cases, a part of the raw material lignocellulosic material may remain as it is in an insoluble state. This liquefied solution itself is extremely useful as various resin raw materials as already described, and adhesives, molding materials,
It is effectively used as a resin raw material in a wide range of fields such as fillers, foams and paints.

[0032]

According to the present invention, it is possible to obtain a liquefied solution having a biomass concentration of 35% by weight or more, which has been impossible in the past. That is, a lignocellulosic material such as wood having a liquid ratio (however, liquid weight = weight of liquefied solvent / total weight of lignocellulosic material and starch) of 1.5 or less is put into a polyhydric alcohol,
With the progress of liquefaction by heating, re-condensation of the liquefied lignocellulosic components due to recondensation occurs,
Unlike the conventional method in which the concentration of the liquefied lignocellulosic low molecular weight substance could not be increased to 35% by weight or more, according to the present invention, starch was liquefied to obtain a liquefied lignocellulosic substance. It is possible to increase the biomass concentration to 35 to 75% by weight while having the characteristics of.

The resulting liquefied solution has a large number of functional groups, particularly a functional group as a polyol, and thus has high reactivity. For example, when a urethane foam is intended, it becomes a polyol resin raw material particularly suitable for urethane foaming. It is extremely useful as a resin raw material. In addition, it will open the way for effective reuse of wood, waste paper, etc.

[0034]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples.

[0035]

[Comparative Example 1] Absolutely dried birch wood flour (20-80 mesh)
80/20/3 weight ratio, which was uniformly mixed beforehand
Polyethylene glycol 400 (PEG400) / glycerin / sulfuric acid mixture of 1.2, 1.5, 2 and 3
A total of about 100 g of the above composition was charged into a 200 ml three-neck glass flask and reacted at 150 ° C. for 40 to 180 minutes to liquefy. After the completion of each reaction time, a dioxane / water mixed diluted solution having a weight ratio of 8/2 was added to each reaction solution in a large excess (about 5 times amount) to dilute, and the mixture was stirred at room temperature for 4 hours.
It was filtered under reduced pressure using "Toyo GA 100" glass filter paper. The residue on the filter paper was repeatedly washed with a dioxane / water mixed diluent having a weight ratio of 8/2 until the furnace liquid became colorless, dried at 105 ° C. to a constant weight, and weighed to calculate the residue rate. However, the residue rate was calculated by the following formula.

[0036]

The results are shown in Table 1. In Table 1, when the liquor ratio is the largest, the liquefaction proceeds most rapidly, and it is almost completely dissolved in the liquefaction of 150 minutes or more, and the residue amount is 7.2% or less in the liquefaction of 80 minutes or more. Even with the liquefaction of minutes, the residue rate is 20% or less.

Even when the liquor ratio is 2, the residue rate decreases uniformly with the liquefaction time, but the liquefaction for 180 minutes shows 2.4%, which means almost complete dissolution. In addition, when the liquid ratio decreases to 1.5 or 1.2, the residue rate becomes 19.8 in the former case.
%, It becomes 32.3% in the latter case, and it can be seen that the value once rises and then sharply rises again. The lower the liquid ratio is, the larger the minimum value (minimum value) of the residue rate is, and the minimum value is obtained in a shorter liquefaction time. That is, when the liquid ratio is less than 2, the liquefaction does not proceed well, and a phenomenon which is interpreted as recondensation of the low molecular weight wood component occurs during the reaction. Liquefaction by charging a large amount of wood flour proceeds to a certain limit,
It is clear that the amount of residue increases, and it can be said that the concentration of wood is limited to about 33.3% (corresponding to a liquid ratio of 2).

[0039]

[Table 1]

Nd: No measured value (because of a large value of 50% or more)

[0041]

Comparative Example 2 Liquefaction was carried out in the same manner as in Comparative Example 1 except that starch (corn starch) was used instead of birch wood flour and the liquid ratio was set to 0.67, 1 and 2, and the results in Table 2 were obtained. Got

It is clear that starch is liquefied much more easily than liquefaction of wood. When treated at 150 ° C for 20 minutes, the insoluble residue was 1.2% (98.8% was liquefied) even if the liquid ratio was 0.67 (starch feed concentration was 60%), and liquefaction was almost complete. I understand. After that, it is also found that recondensation does not occur up to 120 minutes even if heating is continued.

[0043]

[Table 2]

In addition, Table 2 shows that, using several liquid ratios,
It is the residue rate value at each liquefaction time when starch is liquefied at 0 ° C. (liquefaction solution: PEG400 / glycerin / sulfuric acid = 8
0/20/3).

Regarding the liquefaction of this starch, liquefaction was carried out in the same manner as in Comparative Example 1 except that the liquid ratio was fixed at 1 and the catalyst (sulfuric acid) concentrations were 3 parts by weight and 1 part by weight, and the influence of the catalyst concentration was investigated. It was The results are shown in Table 3.

[0046]

[Table 3]

Table 3 shows the residue rate values at each liquefaction time when starch was liquefied at 150 ° C. using several catalyst (sulfuric acid) concentrations (liquefaction solution: PEG400 / glycerin = 80/20; Liquid ratio = 1.0).

It can be seen from Table 3 that the starch is completely liquefied even if the catalyst concentration is lowered to 1/3.

From this comparative example, it is known that starch can be liquefied very easily in the PEG / glycerin system even if the liquid ratio and the catalyst concentration are low, and that recondensation does not occur even after liquefaction for a considerably long time. It was Therefore, the method of liquefying by combining wood flour and starch becomes a practical method for increasing the biomass content in the liquefaction, and a liquefied solution having a high liquefaction concentration can be obtained.

[0050]

Comparative Example 3 In Comparative Example 1, as shown in Table 1, the liquid ratio was 1.
As a 2, 1.5, 2 and 3, a birch wood flour PEG400
/ Glycerin / sulfuric acid = liquefied in the presence of a mixed solution of 80/20/3. On the other hand, in this case, starch was added to each of these liquid ratios, and the liquid ratio with respect to the total amount of wood flour and starch was set to 1.0, and wood flour and starch were simultaneously liquefied. That is, in Comparative Example 1, the mixed solution / wood flour ratio was 11/9 (equivalent to liquid ratio 1.2), 3/2 (equivalent to liquid ratio 1.5), 2/1 (equivalent to liquid ratio 2) and 3 1/1 (equivalent to a liquid ratio of 3) with starch, respectively, mixed solution / wood flour / starch ratio, 11/9/2, 3
Liquefaction was performed in the same manner as in Comparative Example 1 except that the liquid ratios were all set to 1.0, in addition to / 2/1, 2/1/1, and 3/1/2. The results are shown in Table 4.

[0051]

[Table 4]

Nd: no measured value (a considerably large value of 50% or more) *: measured value at 90 minutes

Table 4 shows that PE was obtained by changing the ratio of wood flour and starch.
Residual ratio value when G400 / glycerin / sulfuric acid (80/20/3) solution was mixed at a liquid ratio of 1.0 and various liquefaction times at 150 ° C. and wood powder and starch were simultaneously liquefied Indicates.

From Table 4, as compared with the case of Comparative Example 1, in these cases, the liquefaction proceeded faster up to the first 30 minutes, but the subsequent liquefaction did not proceed relatively, and the residue rate re-increased due to recondensation. It has been found that even shorter liquefaction times become more pronounced. The phenomenon that starch is easily completely liquefied in Tables 2 and 3 is not reflected as it is, and the presence of starch at the same time suppresses the liquefaction of wood flour.

Further, from Table 4 alone, although the four liquefied compositions here have the commonality that the liquid ratio is 1.0, the residual ratio reached and the inversion caused by recondensation occurred. However, it can be said that the difference depends greatly on the wood flour / starch ratio and depends on that ratio. The higher the proportion of wood flour, the higher the residue rate and the faster the recondensation takes place. These tendencies are the same as in Table 1 and can be understood in relation to them, but in any case, it can be said that the addition of starch promotes and increases these phenomena respectively.

On the other hand, comparing the results of Tables 1 to 3,

(1) Liquefaction of wood flour is strongly influenced by the liquid ratio, and satisfactory liquefaction is performed up to a liquid ratio of 2, but recondensation occurs when the liquid ratio is 1.5 or less, Inability to achieve sufficient liquefaction (Table 1),

(2) On the other hand, liquefaction of starch occurs completely even if the liquor ratio is as small as 0.67 (Table 2).

(3) It is understood that the liquefaction of starch is completely liquefied even if the catalyst concentration is reduced to 1/3, and the progress of liquefaction as a whole is hardly affected.

These facts suggest countermeasures against the liquefaction that does not proceed properly when the wood flour and starch shown in Table 4 are liquefied at the same time. That is, it is preferable to adopt the "stepwise liquefaction method" in which wood flour that is affected by the liquid ratio is first liquefied, and then starch that is extremely less affected by the liquid ratio and the amount of catalyst is liquefied. Is. As a result of the examination, it was shown that the adoption of this means is correct as shown in the following Example 1.

[0061]

[Example 1] PEG having a weight ratio of 80/20/3 in which absolutely dried birch wood powder (20 to 80 mesh) was uniformly mixed in advance
A mixture of 400 / glycerin / sulfuric acid mixed solution having a liquid ratio of 2 and a total amount of about 100 g was charged into a 200 ml three-necked flask and reacted at 150 ° C. for 90 minutes to liquefy (in that case, as shown in Table 5, Liquefaction residue rate is 11.5
%).

At that time, the same weight of starch as the initially charged wood flour was added to the flask and charged, and the reaction was continued for another 30 minutes at the same temperature of 150 ° C. to liquefy. After the reaction was completed, a dioxane / water mixed diluent with a weight ratio of 8/2 was added to the reaction solution in a large excess (about 5 times the volume) to dilute the mixture, and the mixture was stirred at room temperature for 4 hours and then mixed with “Toyo GA 100 glass filter paper”. Was filtered under reduced pressure.

The residue on the filter paper was repeatedly washed with a dioxane / water mixed diluent having a weight ratio of 8/2 until the filter paper became colorless, dried at 105 ° C. to a constant weight and weighed to calculate the residue rate. 1 as the residue rate value per weight of wood flour
A value of 1.0% and a residue rate value of 5.5% as a whole biomass charged was obtained. It can be said that this result was obtained in a satisfactory form with a high concentration (about 50% in this case) of the liquefied product.

Table 5 shows the results obtained by tracing the course of this liquefaction by experiments.

In Table 5, the "stepwise liquefaction method" of the present invention
It is clear that the above method makes it possible to maximize the liquefaction of wood flour and starch, and to obtain a liquefied solution with a high concentration (about 50% in this case) that cannot be achieved by liquefaction of wood flour alone. However, it is known that when the liquefaction time is 130 minutes, the amount of the residue is larger than when the liquefaction time is 120 minutes, and the increase in the residue rate due to recondensation has started. In this example, it is known from Tables 2 and 3 that the time required for sufficient liquefaction of starch is 20 to 40 minutes. On the other hand, according to Table 4, when the wood flour / starch ratio which is the same as the final composition of this example is 1/1, 120
It is known that recondensation has started after liquid separation. So, subtract 120 minutes from the 30 minutes required to liquefy starch 90
It is calculated that wood flour should be liquefied up to the minute and starch should be added at that time.

[0066]

[Table 5]

* 1: A stage in which only wood flour is charged and liquefied * 2: Stage of adding starch and liquefying * 3: Add starch at this point

[0068]

Examples 2 to 7 Based on the results of Example 1, except that the amounts of wood flour and starch charged, the first stage liquefaction time and the second stage liquefaction time were changed as shown in Table 6, Liquefaction was performed similarly. The results are shown in Table 7. In each case, suitable liquefaction was performed and a high-concentration biomass liquefaction was obtained.

[0069]

[Table 6]

* 1 Liquefaction solution composition: PEG400 / glycerin / sulfuric acid = 80/20/3 (weight ratio)

[0071]

[Table 7]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // C08J 3/09 C08J 3/09 (72) Inventor Kinichi Shirakawa 4-186 Daikai, Fukushima-ku, Osaka, Osaka Rengo Central Research Institute Co., Ltd. (72) Inventor Koji Kurimoto 4-1-1186 Daikai, Fukushima-ku, Osaka Prefecture Rengo Co., Ltd. Central Research Laboratories (56) Reference JP-A-4-76024 (JP, A) JP A 63-258945 (JP, A) JP-A-2-227434 (JP, A) JP-A-4-106128 (JP, A) JP-A-6-122770 (JP, A) JP-A-62-79230 (JP, A) A) JP-A-61-171701 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08H 5/00-5/04 C08L 1/00-3/20 C08L 97/00- 97/02

Claims (2)

(57) [Claims] 1. A lignocellulosic material is heated in the presence of an acid catalyst and a polyhydric alcohol, starch is added after at least the starting lignocellulosic material has substantially started to liquefy,
A method for producing a lignocellulosic-starch liquefied solution, which further comprises heating. 2. A lignocellulosic material is heated in the presence of an acid catalyst and a polyhydric alcohol, starch is added after at least the starting lignocellulosic material has substantially started to liquefy,
A lignocellulosic-starch liquefied solution which is obtained by further heating and contains 12% by weight or more of a lignocellulosic material, and the total content of the lignocellulosic material and starch is 35% by weight or more.