JPH031351B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides an active cellulose filler with novel performance obtained by heating a cellulose filler and a polymerizable organic acid having an ethylenic double bond, and heating the activated cellulose filler and a polyolefin. The present invention relates to a polyolefin composition obtained by kneading. Conventionally, many technologies have been developed for composite materials in which thermoplastic resins are filled with organic fillers, especially cellulose fillers, with the aim of improving physical properties such as rigidity and mold shrinkage, and reducing costs. Attempts are being made. However, the current situation is that the impact resistance is significantly impaired due to the moisture contained in cellulose-based materials and the lack of adhesion at the interface between cellulose and resin. On the other hand, in recent years, this technology has received increasing attention from the viewpoints of soaring resin prices, resource saving, resource utilization, pollution prevention, and the like. The present inventors have already developed a method and composition for producing a reactive filler obtained by forming a coating reaction layer of an appropriate thickness on the surface of an inorganic filler using an unsaturated organic acid or other functional organic acid. Invented
1239, Special Publication No. 51-1240, Special Publication No. 50-40399, Special Publication No. 52-38581). As a result of further research into active fillers, the present inventors were able to complete a useful activated cellulose filler that could not be obtained with conventional knowledge in organic fillers, particularly cellulose fillers. Ivy. That is, the present invention provides an activated cellulose filler that is inexpensive, can be obtained with high efficiency, and has excellent performance against polyolefin resins. The present invention also provides a polyolefin composition obtained by heating and kneading the above-mentioned activated cellulose filler into polyolefin in a specific ratio. That is, the first aspect of the present invention is to form a monomolecular ultra-thin film on the cellulose surface by heating and reacting a cellulose-based filler with a polymerizable organic acid having ethylenic double bonds, and It is an active cellulose-based filler characterized by having a residual hydroxyl group and an ester bond on the cellulose surface. In addition, the second aspect of the present invention is to form a monomolecular ultra-thin film on the cellulose surface by reacting a cellulose-based filler with a polymerizable organic acid having an ethylenic double bond under dehydration conditions. Activated cellulose filler having double bonds and hydroxyl groups and ester bonds on the cellulose surface 5~
This is a polyolefin composition characterized by being formed by heating and kneading 60% by weight of the polyolefin and 95 to 40% by weight of the polyolefin. A feature of the activated cellulose filler according to the present invention is that the cellulose filler and a polymerizable organic acid monomer having an ethylenic double bond are brought into contact with each other and subjected to a heating reaction. As a result of this reaction, a cellulose-based filler in which the polymerizable organic acid is strongly chemically bonded to the cellulose surface is obtained. Then, by blending the obtained activated cellulose filler with a polyolefin resin and kneading it under heat, a resin composition having extremely excellent mechanical and thermal properties can be obtained. The cellulose filler in the present invention is a filler whose main component is cellulose, such as wood flour, rice husk, pulp, cellulose powder, wood chips, and mixtures thereof, and the particle size thereof is 20 mesh, Preferably, use one finer than 80 mesh. The polymerizable organic acid used in the present invention has a hydrocarbon moiety having one or more ethylenic double bonds, one or more carboxyl groups, and has 10 carbon atoms. The following unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, sorbic acid, α-chloroacrylic acid, and their α,
These include β-substituted compounds, maleic acid, itaconic acid, vinyl acetic acid, allyl acetate, shydroxyethyl acrylate, and the like. In the present invention, higher acid strength is preferred, and acrylic acid and methacrylic acid are particularly effective in the present invention. These can be used alone or in combination.
Used as a mixture of more than one species. Furthermore, acid anhydrides may be used as precursors of polymerizable organic acids. In achieving the present invention, first, the cellulose-based filler and the polymerizable organic acid are reacted,
It is important to form a monomolecular ultra-thin film on the powder surface of the cellulose filler in which the polymerizable organic acid monomer remains firmly bonded with ethylenic double bonds. For this purpose, it is preferable to bring the powdered cellulose filler and the polymerizable organic acid into contact with each other and heat the mixture in the absence of liquid water. Therefore, it is desirable that the cellulose-based filler used be dehydrated and dried in advance so that its attached moisture content is 2% by weight or less, and the polymerizable organic acid used should also be kept to a moisture content of 5% by weight or less. desirable. In order to fully achieve the purpose of the present invention, the amount of the polymerizable organic acid used in the present invention should be approximately 2 Å or more on average and less than 150 Å on average, based on the rough estimation of the surface of the cellulose filler using the BET specific surface area method. In the innermost coating layer, the polymerizable organic acid bound on the surface of the filler exists in a monomolecular thickness, and there is no other free This is the amount that forms a coating film containing a very small amount of polymerizable organic acid with residual ethylenic double bonds. The BET specific surface area method referred to here is a method for measuring the specific surface area of powder using a commonly used adsorption method, and the values used in the description of the present invention are based on the BET method using nitrogen gas adsorption at liquid nitrogen temperature. means the value of specific surface area measured at The specific surface area measurement method is
There are various methods other than the BET method, but this method is the most common and is particularly suitable for fine-particle powders.
In the present invention, the BET method was adopted. Naturally, since the BET method specific surface area is not an absolute value, there is no reason to restrict the present invention. Actually, the weight of the polymerizable organic acid used can be calculated using the following formula. That is, the specific surface area acm ² /g
The weight Wg of the polymerizable organic acid having a specific gravity d that can uniformly coat the surface of the cellulose filler Wg with a thickness bcm is as follows: w=a×W×b×d (g). For example, the amount of polymerizable organic acid that is reacted to the cellulosic filler passing through 300 meshes is most commonly in the range of 1 to 10% by weight. If the amount of the polymerizable organic acid used is less than the range specified in the present invention, the obtained reactive filler may not exhibit sufficient effects as defined in the present invention, and may exceed the range specified in the present invention. If it exceeds this amount, when blended with polyolefin, the appearance of the molded product will deteriorate due to oozing, thermal decomposition, etc. To explain the properties of the coating layer empirically, the ester bonding property with the polymerizable organic acid on the cellulose surface in the present invention is determined by removing unreacted polymerizable organic acid from the active cellulose filler with methanol or the like. Dry, weigh approximately 1g accurately, and add 20ml of 75% ethanol.
Add to the mixture of 20ml of 0.1N sodium hydroxide solution,
This was verified by back titration with 0.1N sulfuric acid after standing at 25°C for 24 hours, and the remaining double bonds were determined by bromide-beronate method. Alternatively, it was found from the shift of the carbonyl group in the infrared absorption spectrum of the activated cellulose filler that the polymerizable organic acid forms an ester bond on the cellulose surface. The method for producing the active cellulose filler of the present invention is a method in which the cellulose filler and the polymerizable organic acid are reacted with each other in the above concentration range with high efficiency in various mixers. As the various mixers, various general powder mixers can be used, but high-efficiency mixers such as a Henschel mixer, Schuler, and ribbon blender are particularly preferred. Furthermore, in order to increase the contact efficiency between the cellulose filler and the polymerizable organic acid, it is desirable to add the polymerizable organic acid to the reaction system in the form of a mist, but it is also possible to add it in the form of a gas. The atmosphere for this reaction can be normal pressure, reduced pressure, or increased pressure, but it is preferable to conduct it in the absence of liquid water, and the moisture generated during the reaction is removed from the reaction system. It is desirable to carry out the process under conditions that will remove it (dehydration conditions). If the reaction is carried out in the presence of excess liquid water, it is difficult to produce the activated cellulosic filler of the present invention. The reaction temperature range for this reaction is above room temperature and below the decomposition temperature of the polymerizable organic acid.
A range of 200°C is preferred. Further, the reaction time range of this reaction is usually in the range of 1 minute to 2 hours, but is generally in the range of 5 to 30 minutes. Furthermore, in order to avoid polymerization of the polymerizable organic acid during this reaction, it is preferable to appropriately select the reaction atmosphere or add a polymerization inhibitor to the polymerizable organic acid. As the polymerization inhibitor, general polymerization inhibitors such as hydroquinone, methoxyhydroquinone, P-benzoquinone, naphthoquinone, and t-butylcatechol can be used, and the amount used is 0 to 1% by weight based on the polymerizable organic acid. A range of 0.02 to 0.5% by weight is particularly recommended. In the present invention, polyolefins include polypropylene, ethylene-propylene copolymer, low-density polyethylene, medium-density polyethylene, high-density polyethylene, polybutene-1, poly-4-methylpentene-1, other olefins, and mixtures thereof. Say what you do. The blending ratio of the active cellulose filler in the present invention is recommended to be in the range of 5 to 60% by weight, preferably 20 to 50% by weight. If it is less than 5% by weight, no filling effect will be obtained, and if it is more than 60% by weight, the moldability will be extremely reduced, the appearance of the molded product will be poor, and the mechanical properties, especially the impact strength, will be significantly reduced. As a device for heating and kneading the polyolefin resin and the activated cellulose filler in the present invention, general kneading machines such as various extruders, Banbury mixers, kneaders, and mixing rolls are used, but heating kneading machines such as a Henschel mixer can be used. A jacketed high-speed flow mixer can also be used. Before feeding to the heating kneading device, a drum blender, V-type blender, ribbon blender, Henschel mixer, and other various premixing machines can be used if necessary. During heating and kneading, a small amount of radical generator may be used to promote the reaction between the polymer radicals of the polyolefin resin and the polymerizable organic acid monomer on the surface of the active filler. Examples of radical generators include tetravalent tin compounds such as dibutyltin oxide, 2,5-dimethyl-2,
5-di(t-butylperoxy)hexane, 2,
5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, dicumyl peroxide, t
- Organic peroxides such as butyl peroxymaleic acid, lauroyl peroxide, benzoyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, isopropyl percarbonate, azo compounds such as azobisisobutyronitrile, The radical generating agent is a commonly used radical generator such as an inorganic peroxide such as ammonium sulfate, and one or a combination of two or more of these may be used. The amount of radical generator used is usually based on 100 parts by weight of the resin composition.
A range of 0.001 to 0.1 parts by weight is suitable. The heating kneading temperature in the present invention needs to be below the decomposition temperature of the cellulose filler and above the melting softening temperature which is the lower limit of the temperature at which polymer radicals are generated due to molecular chain scission of the polyolefin. As a result of various studies, the temperature condition is 150 to 260°C, preferably
The temperature range is 200-230℃. In addition to the above composition, the resin composition of the present invention may contain stabilizers, plasticizers, lubricants, crosslinking agents, pigments, flame retardants, antistatic agents, thickeners, blowing agents, and other additives. . The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the scope of these Examples. In addition, parts and % in Examples and Reference Examples are parts by weight and % by weight, respectively. Wood flour with a particle size of 300 mesh and whose moisture content has been adjusted to 2% or less by drying in advance.
Place 100 parts in a Henschel mixer, heat to 150°C, and while stirring, gradually add 3 parts of acrylic acid containing 500 ppm of hydroquinone in the form of a mist using a spray addition device. The active filler was obtained by mixing for a minute. During the reaction, water vapor was generated, but this was removed from the system in gaseous form. The obtained active filler was thoroughly washed with methanol to remove unreacted acrylic acid, dried, approximately 1 g was accurately weighed, and added to a mixture of 20 ml of 75% ethanol and 20 ml of 0.1N sodium hydroxide solution. After standing for 24 hours at °C, the consumed sodium hydroxide was reduced to 0.1N.
Back titration with sulfuric acid revealed 1.50 parts of ester in terms of acrylic acid. At the same time, when the purified activated wood flour was measured for ethylenic double bonds by the bromide-bromate method, it was confirmed that 0.45 parts of double bonds remained in terms of acrylic acid. In order to confirm the effectiveness of the obtained active filler,
30 parts of the activated wood flour was prepared with MI3.0, density 0.91, 70 parts of polypropylene powder with ethylene content of 5%, and 0.04 part of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane as a radical generator. After mixing, the mixture was melt-kneaded for 3 minutes using a Banbury mixer at a resin temperature of 200 to 230°C, formed into a sheet using two rolls, and then pelletized. This pellet was molded into a test piece using an injection molding machine at a molding temperature of 200°C. The results of the evaluation using this test piece are shown in the first
Shown in the table. In addition, the evaluation method was measured based on the following. Bending strength: ASTM D-790 Flexural modulus: ASTM D-790 Izot impact strength: ASTM D-256 Examples 1-2 to 1-5 Instead of the acrylic acid used in Example 1-1,
Activated fillers were produced in the same manner as in Example 1-1, except that maleic anhydride, maleic acid, itaconic anhydride, and itaconic acid were used and dissolved in a small amount of ethanol, and the same evaluation was performed. . The results are shown in Table 1. Reference Example 1-1 Evaluation was carried out in the same manner as in Example 1-1 except that inactivated wood powder that had been simply dried was used, and the results are shown in Table 1. As seen in Table 1, the activated cellulose according to the present invention and the composition containing it have significantly improved impact strength, stiffness, and strength compared to the unactivated cellulose.

[Table] Examples 1-6 to 1-8 Instead of the wood flour used in Example 1-1, wood flour that passed 50 meshes, pulp powder (manufactured by Sanyo Kokusaku Pulp, product that passed 450 meshes), and waste paper powder were used, respectively. An active filler was produced in the same manner as in Example 1-1, except that it was used, and the same evaluation was performed. The results are shown in Table 2. Reference Examples 1-2 to 1-4 Using the cellulose fillers used in Examples 1-6 to 1-8 that were simply dried, Example 1-1
The same evaluation was conducted and the results are shown in Table 2.

[Table] Example 1-9 Test pieces were obtained in the same manner as in Example 1-1, except that high-density polyethylene (MI10 density 0.96) was used, and the evaluation results are shown in Table 3. Reference Example 1-5 A test piece was obtained in the same manner as Reference Example 1-1 except that high-density polyethylene (MI10 density 0.96) was used, and the evaluation results are shown in Table 3. Examples 1-10 and 1-11 Example 1-1 except that the amount of activated wood flour was changed to 20 and 60 parts, respectively.
Test pieces were obtained in the same manner and the evaluation results are shown in Table 4. Reference Example 1-6 In Example 1-1, the amount of activated wood flour
A test piece was obtained in the same manner as in Example 1-1 except that the amount was changed to 0.10, 70 parts, and the evaluation results were evaluated in the fourth test piece.
Shown in the table.

【table】

[Table] As described above, by using the activated cellulose filler of the present invention, it is possible to provide a composition with outstanding rigidity, impact resistance, etc. when blended with a thermoplastic resin, especially a polyolefin. It is.

Claims (1)

[Claims] 1. A monomolecular ultra-thin film is formed on the cellulose surface by heating and reacting a cellulose-based filler with a polymerizable organic acid having an ethylenic double bond,
An active cellulose-based filler characterized in that it has residual ethylenic double bonds and ester bonds with hydroxyl groups on the cellulose surface. 2. By reacting a cellulose-based filler with a polymerizable organic acid having an ethylenic double bond under dehydration conditions, a monomolecular ultra-thin film is formed on the cellulose surface, and the ethylenic double bond remains and the cellulose is A polyolefin composition characterized in that it is made by heating and kneading 5 to 60% by weight of an active cellulose filler having surface hydroxyl groups and ester bonds and 95 to 40% by weight of a polyolefin.