JPS6244574B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improving the thermal stability of vinyl chloride resin compositions reinforced with talc. In recent years, research has been conducted in various fields to impart mechanical strength and heat resistance to thermoplastic resins by compounding them with inorganic fillers, and some have already been put into practical use. Regarding polyvinyl chloride, reinforcement with glass fibers is known. Other fillers include asbestos,
Wollastonite, gypsum fiber, etc. are being studied. These fibrous fillers are oriented in the flow direction during molding, resulting in anisotropy in physical properties, and have the disadvantage that physical properties in the direction perpendicular to the flow are extremely low. Mica and talc are fillers with low anisotropy, but even when mica is filled into polyvinyl chloride, the aspect ratio (length to thickness ratio) decreases due to shearing force during molding, resulting in poor physical properties. Strengthening properties are lost. In this regard, although talc has the ability to strengthen physical properties and has small anisotropy, it significantly accelerates the deterioration of polyvinyl chloride, resulting in "staining" during molding.
The drawback was that the molded product was easily colored black. It is generally known that blending inorganic fillers with polyvinyl chloride accelerates the deterioration of the polyvinyl chloride, and the reason for this is that iron ions, etc. contained as impurities accelerate dehydrochlorination of the polyvinyl chloride. It is said. Asbestos-polyvinyl chloride is often used as so-called PVC tiles, but in this case, various studies have been conducted to improve its thermal stability. , dicyandiamide and melamine are said to have a large effect on improving thermal stability. It has been found that even if one part of dicyandiamide or melamine is added to 100 parts of polyvinyl chloride compound containing talc, the former further reduces the thermal stability, while the latter has little effect. or,
Even if tribasic lead sulfate or butyltin malate, which has excellent effects as a stabilizer for polyvinyl chloride, is added, the effect is hardly seen. As a result of extensive research to improve the thermal stability of talc and polyvinyl chloride composites, the present inventor found that when a polyamide with a softening point or melting point of approximately 200°C or less is added to a vinyl chloride resin containing talc, the temperature increases significantly. The present invention was developed based on the discovery that this method has the effect of improving stability. The details will be explained below. The talc of the present invention has a mineral composition of Mg ₃
(Si ₄ O ₁₀ ) (OH) ₂ monoclinic mineral,
Crushed ore is used. The shape of the crushed talc is flaky. For grinding talc,
Jaw crushers, Hammer crushers, Impact
A crusher or pulverizer such as a mill is used, but
A crusher belonging to the Impact mill family is preferred. More preferably, a centrifugal force classification type mill is used, such as Super Micron Mill (Hosokawa Iron Works), Mikro
These include Atomiser (USA), Raymond vertical mill (USA), and Ultra contra-plex muhle (Germany).
More preferably, it is pulverized using a crusher belonging to an impact mill, and then classified using an Archimedean vortex classifier. Mikroplex by Alpine is known as this type of classifier. In this case, it is necessary to adjust the blade angle and repeat the same operation several times. Other zigzag rotating wall classifiers (Alpine) may also be used. or
It can also be obtained by milling several times using easily crushed talc ore. Depending on the need,
Talc may be used after surface treatment with silane, coupling agent, organic titanate, fatty acid, etc. The amount of talc to be filled into the polyvinyl chloride resin is preferably 5 to 40% by weight. The polyvinyl chloride resin referred to in the present invention refers to polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride, vinylidene chloride copolymer, copolymer of vinyl chloride and vinyl acetate, maleic anhydride, ethylene, propylene, etc. , modified resins such as chlorinated polyvinyl chloride resins, which can be used alone or in combination. Also ABS,
Resins for improving impact resistance such as MBS and chlorinated polyethylene can also be mixed. As compounding agents, lead-based, tin-based, Ca-Zn-based stabilizers, lubricants, and processability improvers can be added. If necessary, other fillers such as calcium carbonate, gypsum, gypsum fiber, asbestos, mica, calcium silicate, etc.
Glass fiber or the like may also be used in combination. The polyamide of the present invention having a softening point or melting point of about 200°C or less is a polyamide having a -CONH- bond and an ASTME-28
- It is a linear polymer with a softening point measured by the ring and ball method of 58T or a melting point measured by the DSC method (main melting peak temperature using a differential calorimeter) of approximately 200℃ or less. To explain in more detail, nylon 6, nylon 6.6, nylon 11, and nylon 12, which are well-known homopolymers of general polyamides, have high crystallinity, so their melting point is much higher than that of the present invention, and when molded with vinyl chloride resin. At resin temperature, it does not soften and has no effect.
In order to lower the softening point or melting point to about 200°C or less, it is necessary to disrupt the crystallinity of polyamide, and this can be done by copolymerization such as nylon 6/6.6/6.10 or nylon 12 multi-component copolymer. Those with disturbed crystallinity, modified nylons such as methoxymethylated nylon 6 and methoxymethylated nylon 6.6 modified by alkoxymethylation, and unsaturated fatty acids.
Examples include polyamide resins made by reaction polymerization of dimer acid dimerized by Diels-Alder reaction and ethylenediamine. Furthermore, polyamides modified with unsaturated acids, phenols, etc. are also included. Among such polyamides, those with a high free amine concentration do not exhibit sufficient effects, and some polyamide stabilizers may inhibit the thermal stability of polyvinyl chloride, so care must be taken. The method of mixing the polyamide of the present invention is arbitrary, but for example, the polyamide of the present invention may be added to a vinyl chloride resin compound containing talc and mixed, or the polyamide of the present invention may be added to talc in advance and heated. It may be added to the vinyl chloride resin compound after mixing, or talc may be surface-treated if it is a solvent-soluble polyamide.
When the amount of polyamide used in the present invention exceeds 25% by weight relative to talc, the effect is small;
Also, if the amount used is less than 0.1% by weight relative to talc, the effect will be small, so it is preferable to use approximately
It is best to use 0.1 to ~25% by weight. The amount of talc used in the present invention is such that if it is added alone to a vinyl chloride resin, the thermal stability will be significantly lowered, but even in this case, the present invention has the effect of greatly improving the thermal stability. be. The effect of the present invention is great even when a large amount of talc is added, but if the amount of talc used exceeds 40% by weight, it is difficult to mold and process, and the physical properties are also poor, so it is recommended to use less than 40% by weight. It is preferable to do so. Molding of the vinyl chloride resin composition of the present invention can be carried out in a conventional manner after adding necessary additives, but it is important to mix the talc and vinyl chloride resin so that they are sufficiently initially dispersed. desirable. For example, measures such as mixing at high speed for about 20 minutes or pre-kneading with a Banbury mixer are taken, although it cannot be generalized depending on the machine.For molding, measures such as two-roll, single-screw extruder, twin-screw extruder, special Direct molding using a compound mixer, or producing pellets using a two-roll, Banbury mixer, single-screw extruder, twin-screw extruder, or special compound compounder, followed by injection molding, blow molding, or extrusion. The molding material may be obtained by molding, calendering, melt spinning, or the like. Talc has traditionally been used as a filler for polystyrene and polyolefins, but it is rarely used for vinyl chloride resins, except for applications where heat stability is not required, such as in paints, or applications where large amounts of plasticizers are used, such as in soft materials. It had not been put into practical use. One of the reasons for this is that the polyamide of the present invention has extremely poor thermal stability and is difficult to implement industrially, but the polyamide of the present invention is not a stabilizer, and moreover, the amide group reduces the heat resistance of polyvinyl chloride. Although it is common sense to think that, it is surprising that the presence of talc has a remarkable effect of improving thermal stability, and we believe that it has great industrial utility value. The effects of the present invention will be explained in detail in Examples below. Examples 1 to 8, Comparative Examples 1 to 8 Chinese talc was crushed and classified using a Super Micron Mill (manufactured by Hosokawa Iron Works), and the classification operation was repeated using a Microplex (manufactured by Yaskawa Electric) to obtain particles of 10μ or less.
Talc (hereinafter referred to as talc) having a distribution of 90.4% and 81.1% below 5μ was prepared. Also, 100 parts of polyvinyl chloride (Kanevinyl S-1001), 3 parts of tribasic lead sulfate, 1.5 parts of dibasic lead stearate, 0.5 parts of lead stearate, 0.5 parts of lucium stearate.
1 part and 2 parts of PA-20 (manufactured by Kanebuchi Chemical Co., Ltd.) were heated to 110°C and mixed in a super mixer, and then cooled to obtain a lead-containing compound (hereinafter referred to as base compound). 79 parts of the base compound, 20 parts of talc, and 1 part of the following polyamide were mixed in a mixer, and the thermal stability was measured using a kneader type Plastograph (Brabender). Figure 1 shows a typical plastograph, and Table 1 shows the maximum torque ( _MB ), steady torque holding time (△T ₁ ), and time from maximum torque to the start of decomposition (△T ₂ ). The measurement conditions for Plastograph were to use a chamber with an internal volume of 55 c.c., a set temperature of 190°C, and a preparation amount of 73.
g, preheating time was 4 minutes, and rotor rotation speed was 40 rpm. As shown in Figure 1, △T ₁ and △T ₂ are the points 0.1Kg-cm higher than the lowest torque (Tc), respectively.
Tc and maximum torque generation time T _B were defined as △T ₁ = Tc - (Tc) and △T ₂ = Tc - T _B. Amiran CM-8000 (Toray) Melting point: 128°C...Example 1 Bar Salon 1200 (Japan General Mills Chemical) Softening point: 200°C...Example 2 Bar Salon 1164 (Japan General Mills Chemical) Softening point: 160°C...Example 3 Bar Salon 1117 (Japan General Mills Chemical) Softening point 117°C...Example 4 Barsalon 1300 (Japan General Mills Chemical) Softening point 95°C...Example 5 Milvex 1000 (Japan General Mills Chemical) Softening point 135°C...Example 6 Milvex 1235 (Japan General Mills Chemical) Softening point 200℃...Example 7 Amiran CM-8000 AA ^{20 (} Note ¹⁾ Melting point approximately 120℃...Example 8 (Note 1) CM-8000 powder was dispersed in water and 2N-
Acrylic acid is grafted by dropping H ₂ SO ₄ solution and 20 parts of acrylic acid, and then adding ceric ammonium sulfate. For comparison, base compound...Control example 1 80 parts of base compound and 20 parts of talc... 〃 2 〃 79 parts and 20 parts of talc and 1 part of tribasic lead sulfate...Control example 3 〃 〃 1 part of butyltin malate...Control Example 4 Urea 1 part...Control Example 5 Dicyandiamide 1 part...Control Example 6 Melamine 1 part...Control Example 7 Nylon 6.6 1 part...Control Example 8

[Table] As can be seen from the comparison between the base compound of Control Example 1 and Control Example 2 with added talc, △T ₁ is 1/7, △
It can be seen that by adding about 1/4 of talc to _T2 , the thermal stability decreases significantly, but even if tribasic lead sulfate, which is a stabilizer for vinyl chloride, or butyl tin malate is added to this, Almost no effect was observed (Control Examples 3 and 4). Even when urea, dicyandiamide, and melamine are added, which are effective in improving the thermal stability of asbestos-vinyl chloride composites, there is almost no effect, and in some cases the effect is even reduced. In the case of the polyamide of the present invention, which is found to be difficult to improve (Comparative Examples 5 to 7), △T ₁ is 2.2 to 3.3 times, and △T ₂ is 1.7 times, depending on the addition.
It can be seen that the thermal stability is significantly improved by ~2.9 times. (Examples 1 to 8) In the case of a polyamide with a high melting point such as nylon 6.6, although it is outside the scope of the present invention, almost no effect is observed, and the melting point or softening point must be approximately 200°C or less. It is shown that. Examples 9 to 14 Using the base compound of Example 1, talc, and Amilan CM-8000, mix them in the following formulation,
The plastograph was measured using the same method as in Example 1, and the results are shown in Table 2. Base compound 79.9 parts, talc 20 parts CM-8000, 0.1 part ...Example 9 79.7 parts 20 parts 0.3 parts ...Example 10 79.5 parts 20 parts 0.5 parts ...Example 11 79 parts 20 parts 〃 1.0 parts …Example 12 〃 78 parts 〃 20 parts 〃 2.0 parts …Example 13 〃 75 parts 〃 20 parts 〃 5.0 parts …Example 14

[Table] The amounts of CM-8000 added in Examples 9 to 14 correspond to 0.5, 1.5, 2.5, 5.0, 10.0, and 25% by weight of talc, respectively, but adding only 0.5% by weight to talc results in a large amount of CM-8000. Thermal stability has been greatly improved, from a peak of 1.5 to 2.5% by weight to 25% by weight, based on talc.
Although the improvement effect decreases compared to the peak, a comparison with Control Example 2 shows that it has been greatly improved. Even if the polyamide of the present invention is added, the maximum torque remains the same or shows a tendency to increase, which is a surprising and unique effect that is essentially different from the improvement of thermal stability by imparting lubricity. Examples 15 to 18, Comparative Examples 9 to 12 In order to examine the thermal stability effect due to the content of talc, the following formulations were made in the same manner as in Example 1, using 2.5% by weight of CM-8000 based on talc. The plastograph was measured and the results are shown in Table 3. In addition, considering the specific gravity, the amount of Plastograph sample prepared was as follows: base compound 66.0g, talc 5% by weight 67.6g, talc 10% by weight 96.2g, talc 15% by weight 70.8g, talc 20% by weight 73g, talc 30% by weight. A weight percent of 76.4 g was used. Base compound 94.875 parts, talc 5 parts, CM-8000...0.125 parts...Example 15 89.75 parts, 10 parts, 0.25 parts...Example 16 84.625 parts, 15 parts, 0.325 parts ...Example 17 Base compound 79.5 parts, talc 20 parts, CM-8000...0.5 parts...Example 11 〃 96.25 parts, 〃 30 parts, 〃 ...0.75 parts...Example 18 〃 95 parts, 〃 5 parts, ... Comparative example 9 90 copies, 10 copies, … 10 85 copies, 15 copies, … 11 70 copies, 30 copies, … 12

【table】

[Table] When 5% by weight of talc is added to the base compound, △T ₁ and △T ₂ decrease significantly, and when they increase to 30% by weight, they tend to decrease further. The amide of the present invention (in the example,
When CM-8000) is added in an amount equivalent to 2.5% to talc, the thermal stability is greatly improved. This effect is fully exhibited even when 30% by weight of talc is added.
This is particularly noticeable when talc is less than 10% by weight, showing that the thermal stability is almost the same as the base compound.

[Brief explanation of the drawing]

FIG. 1 is a plastograph of Comparative Example 2 and Example 1, with torque on the vertical axis and time on the horizontal axis. Furthermore, ΔT ₁ and ΔT ₂ are illustrated respectively. Graph 1...solid line, talc 20% by weight (control example 2), graph 2...broken line, talc 20% by weight + CM
-8000, 1.0% by weight (Example 1).

Claims (1)

[Scope of Claims] 1. A vinyl chloride resin composition comprising a vinyl chloride resin containing 5 to 40% by weight of talc and a polyamide having a softening point or melting point of 200°C or less. 2. A vinyl chloride resin composition containing 0.1 to 25% by weight of the polyamide according to claim 1 based on talc.