JP3423112B2 - Cellulose derivative resin composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic filler to which dimensional accuracy and dimensional stability, hygroscopicity, heat resistance, mechanical strength and vibration damping property are added. Improved cellulose derivative resin set
About adult . That is, the present invention relates to a cellulose derivative resin composition to which an inorganic filler is added, which has excellent damping properties, low hygroscopicity, excellent dimensional stability, and excellent impact resistance. [0002] Cellulose derivative resins have excellent impact resistance, oil resistance and gasoline resistance, and have low chargeability.
It has the characteristics of good touch and feeling. Furthermore, it has excellent features such as being excellent in moldability, being capable of injection molding, extrusion molding, and hollow molding, and being easy to perform secondary processing such as dyeing, painting, and cutting. Utilizing such features, it is used for tools, mechanical parts, cosmetics, optical products, sports goods, and the like. On the other hand, it has good vibration damping properties and sound absorbing properties, and is used as a component for acoustic equipment such as a musical instrument keyboard. Attention has been paid to the keyboard of some musical instruments for their characteristic of absorbing sound of 3000 Hz or more more remarkably than other resins, and cellulose derivative resins to which specific silica is added have been used. [0003] On the other hand, the use of a keyboard or other metal or plastic by bonding or joining has come to be performed. In such use, strict dimensional accuracy is required. It has become. On the other hand, the cellulose derivative resin generally has water absorbency, and its dimensions may change due to moisture absorption and release due to environmental humidity. [0004] Therefore, the water absorption has been reduced by increasing the amount of plasticizer added to the cellulose derivative resin, and the dimensional stability has been improved. [0005] However, when the plasticizer is increased, the impact strength,
Although tensile elongation at break improves, heat deformation temperature, hardness,
The tensile strength and the flexural modulus will change. On the other hand, in order to improve mechanical and chemical performance and to improve dimensional stability, a filler is used.
It has been generally attempted to add They are,
It is also called a functional filler, and most of them are inorganic fillers. Generally, there are a fibrous form, a flat flake form, and a powder form. However, fibrous materials such as glass fiber and carbon fiber generally have a diameter of several μm to several tens μm, and have a function of improving mechanical strength and dimensional stability. There has been a problem that the processability is deteriorated, and the fiber is reflected on the appearance, the surface is roughened and the quality of the appearance is impaired. Further, when it is intended to ensure formability and workability by using fibrous or plate-like flakes, it is necessary to add a large amount of plasticizer, which has led to a decrease in strength and heat resistance. On the other hand, a powdery filler has good moldability, but has little effect on dimensional stability and lowers mechanical strength, making it difficult to achieve its intended purpose. . As described above, a cellulose derivative resin having good dimensional stability, excellent impact resistance and mechanical strength, and excellent vibration damping properties has not yet been found. The present invention is excellent in dimensional stability, impact resistance and heat resistance while maintaining the excellent vibration damping properties of such a cellulose derivative resin, and is also excellent in moldability, especially injection moldability. An object of the present invention is to provide a cellulose derivative resin composition having good appearance quality of a molded article. Means for Solving the Problems The inventors of the present invention have made intensive studies in order to develop a composite cellulose derivative resin having an excellent balance of the above properties. As a result, the cellulose derivative resin has a specific diameter and aspect ratio. It has been found that a composition in which a filler having a specific ratio is blended in a specific ratio can be suitable for the purpose, and the present invention has been completed. That is, the present invention
An object of the present invention is to provide a cellulose derivative resin composition characterized by dispersing and complexing an inorganic whisker as a functional filler in a cellulose resin. In that case, of course, a plasticizer is also added. Hereinafter, the present invention will be described in detail. There is no particular limitation on the cellulose derivative resin used in the present invention, cellulose acetate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, nitrocellulose resin, ethyl cellulose resin,
Cellulose propionate resins, although such butyrate cellulose acetate resins, cellulose acetate resins, cellulose propionate resin is desirable. [0013] The inorganic filler of the present invention the composition, after
As is clear from the examples described below, potassium titanate is
used. Such a ceramic whisker may be a hydrate containing water of crystallization. [0014] Examples of the filler amount, has the good to use 5 to 20 parts by weight per 100 parts by weight of the material cellulose derivative resins. If the filler is less than 5 parts by weight , dimensional stability,
If the impact strength is not improved, and if it exceeds 20 parts by weight, the fluidity decreases, molding, especially injection molding, becomes difficult, and the molding temperature becomes higher, causing deterioration and coloring of the resin and roughening of the product appearance. Will occur. [0015] The average diameter of the filler, 15 [mu] m
The following, preferably 1 μm or less, is used. According to such a filler, since the fiber diameter is small, it is possible to uniformly fill and disperse into a thin portion or a narrow portion of a molded product, and precision molding and thin molding can be performed, and micro reinforcement is made. . That is, when the filler used in the present invention is added to plastic, the average diameter is about 1 μm and the shape of whisker having an average aspect ratio of 20 or more improves the mechanical properties without impairing the workability,
In addition, a cellulose derivative resin having excellent dimensional stability as well as surface smoothness can be obtained. On the other hand, the average diameter is 0.1
If it is less than μm, the strength of the filler is small and the effect on dimensional stability is reduced, which is not suitable. Therefore, the average diameter of the inorganic filler was 0.1 to 15 μm. Further, when the average aspect ratio of the filler is less than 20, improvement in impact resistance, which is one of the functions of the fibrous filler, cannot be expected, and the impact resistance deteriorates similarly to the granular filler. The average aspect ratio is 20 or more. The potassium titanate whisker of the present invention
By improving heat resistance by Ranaru inorganic filler, it is also achieved improvement in thermal dimensional stability. The cellulose derivative resin composition containing a filler employed in the present invention has an internal friction (tan δ) at 210 Hz of 0.02, which is an index indicating the vibration damping property.
It is 0 or more and can be used as a sound component for musical instruments such as a keyboard, a precision component, a soundproofing material, and a vibration damping material as a material having improved dimensional stability without impairing the vibration damping property. On the other hand, dimethyl phthalate is used as the plasticizer.
(DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), phthalate esters such as diamyl phthalate, triphenyl phosphate (TPP), tricresyl phosphate (TCP) Such as phosphoric acid type, adipic acid type such as dibutyl adipate and dioctyl adipate, citric acid type such as acetyl triethyl citrate and tributyl acetyl citrate, and polyvalent such as triethylene glycol bis (2-ethylhexanoate) Alcohols are typical examples. These plasticizers are used alone or in combination of two or more. It is optimal to use 5 to 50 parts by weight based on 100 parts by weight of the raw material cellulose derivative resin in the present invention. If the amount of the plasticizer is less than 5 parts by weight, the fluidity is remarkably reduced, and molding, especially injection molding, becomes difficult. Further, the molding temperature is increased, and the resin is deteriorated or colored. On the other hand, if it exceeds 50 parts by weight, the fluidity is improved, but the resin itself becomes flexible, the added amount of the inorganic filler is increased to improve the heat resistance and the hardness, and the impact strength is lowered. On the other hand, the cellulose derivative resin composition of the present invention may further contain , as other heat stabilizers generally used for preventing thermal deterioration, for example, weak organic acids, epoxy compounds, phosphites and thioethers. Phosphites, thiophosphites, phenol derivatives, imidazoleamine derivatives, metal soaps, triazoles and hindered amines as ultraviolet absorbers, and dyes and pigments can be appropriately added in usual amounts. The mixing or kneading is performed by a commonly used kneader. The heating temperature at this time is in the range of about 150 ° C. to 300 ° C., depending on the type of the resin and the amount thereof. The cellulose derivative resin composition according to the present invention is efficiently molded by injection molding, but various plastic molding methods such as compression molding, extrusion molding, and hollow molding are applicable. it can. The cellulose derivative resin composition according to the present invention is obtained by dispersing and complexing a potassium titanate whisker having a specific diameter and an aspect ratio as a filler, and has almost no dimensional change due to moisture absorption and heat. because eliminated, excellent dimensional stability, yet it enables ordinary cellulose derivative resins similar molding excellent in mechanical strength, yet 210
When the internal friction (tan δ) at Hz is 0.020 or more, a resin composition having good vibration damping properties of the cellulose derivative resin can be obtained. The cellulose derivative resin composition according to the present invention is used as precision parts, musical instrument parts, and the like by utilizing these characteristics. EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. [Example 1] Cellulose acetate resin 1
20 parts by weight of potassium titanate whisker as an inorganic filler and 35 parts by weight of diethyl phthalate (DEP) as a plasticizer are added to 00 parts by weight, and stirred and mixed at 80 ° C. for 4 hours using a universal mixing stirrer. At the same time, drying was performed so that the water content became 0.2% or less. This mixture was melt-kneaded at 220 ° C. using an extruder having a diameter of 40 mm,
Subsequently, extrusion was performed and pelletized. A test piece was prepared from the pellet by an injection molding machine, and a test by ASTM and a vibration damping property were measured. The results are shown in Table 1 below. [Table 1] In Table 1, the vibration damping property is shown as an internal friction (tan δ) at a temperature of 25 ° C. as a vibration damping property, and the larger the tan δ, the faster (good) the vibration damping, so that it is preferable. The tan δ of the present example is 0.054, which is 2.5 to 6 times the value of 0.009 for polystyrene, 0.014 for ABS, and 0.021 for polyethylene. This indicates that the vibration damping is 2.5 to 6 times faster, indicating that the characteristics are good. [Examples 2 to 6] On the other hand, pellets were prepared in the proportions shown in Table 2 below, each containing cellulose propionate as a base resin, potassium titanate whisker as an inorganic filler, and a plasticizer. Table 2 also shows the measurement results of the physical properties. [Table 2] In all the examples, tan δ is 0.030 or more, 0.009 for polystyrene and 0.01 for ABS.
4. The value is 1.5 to 4 times that of 0.021 of polyethylene, which means that the vibration damping is 1.5 to 4 times faster, and the characteristics are good. I understand.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08K 7:08) (72) Inventor Masahiko Abiko 200 Terashimacho, Hamamatsu-shi, Shizuoka Prefecture Kawai Musical Instruments Co., Ltd. (72) Inventor Fuku Motoaki 200, Terashimacho, Hamamatsu City, Shizuoka Prefecture Inside Kawai Musical Instruments Manufacturing Co., Ltd. (72) Inventor Masaya Onishi 397-1 Kamiemobe, Yobe Ward, Himeji City, Hyogo Prefecture References JP-A-3-281574 (JP, A) JP-A-8-283456 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3 / 00-13/08

Claims (1)

(57) [Claim 1] A potassium titanate whisker having an average diameter of 0.1 to 15 µm and an average aspect ratio of 20 or more is used as an inorganic filler with respect to 100 parts by weight of a cellulose derivative resin. 5-20 parts by weight and a plasticizer 5-50
A cellulose derivative resin composition having an internal friction (tan δ) at 210 Hz of 0.020 or more obtained by adding parts by weight.