JPH0541721B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a viscose rayon filament intended for use in polishing, brushing, etc., and a method for producing the same. <Conventional technology> Traditionally, in the machinery and metal industries, precision machining processes such as grinding and polishing have been performed in order to obtain high dimensional accuracy and smooth finished surfaces. A wide variety of equipment has been devised and used. For example, abrasive brushes, abrasive wheels, abrasive cloth paper, etc. are known. The abrasive brushes mentioned above are generally rubbed at high speeds, and the frictional heat generated by contact between the abrasive brush and the object to be polished becomes extremely high. As is often the case with materials, the tip of a linear object melts and deforms, changing the characteristics of the abrasive brush.
It was not desirable as an abrasive brush. Abrasive grains used for precision machining include diamond, emery, corundum, diatomaceous earth, garnet, etc. as natural products, and Al ₂ O ₃ , SiC,
WC, Fe ₂ O ₃ , Cr ₂ O ₃ , MgO, etc. are used, but
In view of ease of use, these abrasive grains are often mixed with stearic acid, beef tallow, resin, wax, mineral oil, etc., formed into a solid rod, and rubbed onto an abrasive substrate. Furthermore, during polishing, a working fluid with petroleum as its main component and sulfurized oil or animal oil added is used to smooth the finished surface, wash away polishing debris, and dissipate the heat generated by friction. There is also. Abrasive brushes are naturally required to be made of materials that are not affected by these organic substances or do not absorb and swell.By using such materials, it is possible to retain the abrasive material through the use of organic substances as a medium, and at the same time, it is not affected by the working fluid. never be done. As mentioned above, a linear material for abrasives is required to have heat resistance and organic solvent resistance, but there is still no brittle that has both of these properties in synthetic fiber materials such as nylon and polyester. On the other hand, natural cellulose fibers such as cotton and sisal, which are used for buffing, and tampico, which is a type of cactus, are examples of materials having heat resistance and organic solvent resistance. Since cotton and sisal are natural products, the denier of the filament is limited, and it is not possible to obtain a linear material that is adjusted to meet the requirements for waist strength. Also, since it is a natural fiber, it may not be possible to produce yarn with a uniform denier. For example, in the case of Tampico fiber, even if the average denier is 600, the variation can reach 300 denier. Cellulose-based artificial fibers have heat resistance and organic solvent resistance, and are advantageous in that they can be formed into a certain shape by spinning and have uniform properties and performance. Therefore, viscose rayon linear products have been provided as linear products for abrasive materials. However, conventional viscose rayon linear products have a drawback in durability, and it has been desired to improve this. <Problems to be Solved by the Invention> As described above, heat resistance and organic solvent resistance are indispensable properties for linear materials used in polishing brushes. The present inventors have conducted intensive research to develop a viscose rayon linear material that takes advantage of these properties of cellulose and has improved physical properties and increased durability, and has now accomplished the present invention. An object of the present invention is to provide a viscose rayon linear material for use in abrasive brushes, which is essentially durable and resistant to organic solvents, and which has improved durability, and a method for producing the same. <Means for Solving the Problems> The object of the present invention is to provide a viscose sleigh linear product having a single yarn of 300 to 5000 deniers, characterized in that the stress peak temperature in the heat shrinkage stress curve is 180 to 200°C. achieved by. If the filament denier of the viscose rayon filament is less than 300 denier, it will be too stiff and cannot be used for brushes, and if it exceeds 500 denier, it will become brittle. Thermal shrinkage stress is measured by fixing the sample on a straight line, increasing the temperature of the sample over time, and measuring the shrinkage stress that occurs due to heating. It is generally said that the more molecular chains there are in the amorphous region, the greater the amount of molecular chains in the amorphous region. The present inventors found that viscose rayon linear products with a stress peak temperature of 180 to 200°C in a heat shrinkage stress curve exhibit a maximum value of the product of tensile strength and elongation (hereinafter referred to as toughness). I discovered that. That is, when the peak temperature of the heat shrinkage stress curve exceeds 200°C, the toughness decreases, and even below 180°C, the toughness is low. Toughness indicates the most basic physical property of a yarn, and the peak temperature of the heat shrinkage stress curve is
The viscose rayon linear material exhibiting a temperature of 180-200℃ is
It is thought to have an internal structure suitable for yarn, and has an extremely high toughness of 40 or more, and to date no viscose rayon filament exhibiting such high toughness has appeared. In addition, the peak temperature of the heat shrinkage stress curve is 180 to 200℃.
The viscose rayon linear material exhibiting the following shows the maximum value for other excellent properties, namely, the straightness characteristic of the linear material necessary for a linear material for an abrasive brush. Straightness of a linear object is that the linear object is straight, and when the linear object is suspended by its own weight,
Empirically, it is preferable that the waveform enters and exits at an angle of 8° or less with respect to the fiber axis. The straightness of the linear object is particularly important as it effectively transmits the polishing force to the surface to be polished. If the peak temperature of the heat shrinkage stress curve is less than 180°C, a linear product with preferable straightness cannot be obtained. In addition, the characteristics required for a linear material for an abrasive brush include the product of knot breaking strength and elongation, and the product of loop breaking strength and elongation (hereinafter abbreviated as the knot strength and elongation product and the loop strength and elongation product, respectively). ). When the linear material for abrasive brushes is put into practical use,
Although it is always used while being gripped by a fixture such as a plate, the bending stress applied to the linear object during the polishing operation is concentrated at this gripping point. Particularly in the case of viscose rayon linear objects, the concentration of bending stress causes the problem of breakage of the linear object at the gripping point, which improves physical properties such as knot strength and elongation products and loop strength and elongation products. is important. The viscose rayon linear product of the present invention has excellent straightness and exhibits high values of the knot strength and elongation product and the loop strength and elongation product. In addition, as mentioned above, the viscose rayon linear material has high toughness and is therefore strong and durable, and even when used for abrasive brushes, it is less likely to break at the gripping point, and has excellent performance. It is. The second aspect of the present invention is that after washing, the filament obtained without stretching in the spinning process is first contracted by 3 to 15% without applying tension in the drying process, and then constant length drying is performed. This is a method for producing a viscose rayon linear product having a single yarn of 300 to 5000 denier. First, the filamentous material spun in the spinning process is not drawn. In other words, viscose rayon filaments of 300 deniers or more solidify and regenerate slowly and are non-uniform in the cross-sectional direction, so that if they are stretched, the roundness of the cross-section will be impaired. In addition, since the stretching is non-uniform, the resulting structural distortion affects the subsequent steps, which is undesirable as it lowers the physical properties of the linear product. Next, the obtained linear material is washed and then shrunk in two stages in a drying process. For example, the linear material after washing is wrapped around a winding frame in one to several layers. Winding up, then the shrinkage rate of the linear material is 3
After reducing the frame circumference of the winding frame to ~15%,
Heat and dry. By doing this, the linear material is first dried and shrunk by 3 to 15% without applying tension, and then the length after shrinkage is fixed and final drying is performed to form a single yarn of 300 to 5,000 deniers of viscose rayon. can manufacture things. When the shrinkage rate of the linear material is less than 3%, the peak temperature of the heat shrinkage stress curve exceeds 200°C. Moreover, when the shrinkage rate is 15% or more, the peak temperature of the heat shrinkage stress curve becomes less than 180°C. A more preferable range of shrinkage is 4 to 13%. The manufacturing method of the present invention is thus a method in which drying is performed without applying tension at the initial stage of drying, and conversely, drying is performed while applying tension at the final stage of drying. That is, in the first step, a stress-free drying step, the structural strain inherent in the linear object is relaxed and removed, and in the second step, a tension drying step, the linear object is stretched to improve its orientation. The present invention makes it possible to adjust the influence of the two-stage drying process on the structure and properties of the linear object and achieve an appropriate balance by controlling the shrinkage rate of free shrinkage in the first-stage stress-free drying process. can. In this way, the viscose rayon filament is spun into a single yarn of 300 to 5,000 deniers, wound on a winding frame, and then shrunk and dried in two stages, resulting in a viscose rayon wire with desirable performance as an abrasive brush. It is possible to produce products like this. The definition of each physical property described in this specification and its measurement method will be explained below. (1) Peak temperature of stress in heat shrinkage stress curve Heat shrinkage stress strain measuring device (TMC manufactured by Shimadzu Corporation)
30), the denier of the yarn to be measured x 3 x 10 ^-3
After adjusting by applying an initial load of g, the sample length after setting the sample is set to 5 mm, and the temperature is increased at a heating rate of 5° C./min to obtain a heat shrinkage stress curve. The temperature at which stress peaks from this curve is defined as the peak temperature. The samples used were immediately transferred to an atmosphere with a relative humidity of 65% and a temperature of 25° C. after drying and stored for 60 hours. The following (2), (3), and (4) were measured using a tensile tester (Autograph DCS-100 manufactured by Shimadzu Corporation). (2) Strength and elongation product Measure the maximum tensile load and maximum elongation of a sample with yarn length of 2 cm. Next, the strength is determined from the maximum load and the denier of the thread, and the product of strength and elongation is calculated. (3) Product of knot strength and elongation Tie a sample of yarn length 20 cm at the center, measure the maximum tensile load at this time and the maximum elongation, calculate the strength in the same way as in (2), and calculate the relationship between strength and elongation. Calculate the product. (4) Loop strength elongation product Using two samples with a length of 20 cm, connect the two in a loop, measure the maximum tensile load and maximum elongation, and calculate the strength in the same way as in (2). and calculate the product of strength and elongation. However, in this case, the maximum tensile load is obtained as the sum of the two threads, so
When calculating the strength, use a value multiplied by 1/2. <Examples> The present invention will be specifically explained below by giving examples,
At the same time, a performance comparison with a comparative example will be made. Examples 1, 2 and Comparative Examples 1, 2, 3 Production conditions of Γ Example 1 Viscose (cellulose 8
%, total alkali 5.5%, total sulfur 2.2%, weight percent, viscosity at 20℃ 70 poise) 1.2mm
Using a φ×1 ^H spindle and a spinning speed of 50 m/min, sulfuric acid
130g/, sodium sulfate 200g/, zinc sulfate
15g/, Spun without stretching in a spinning bath with a bath temperature of 50℃, washed, and rolled up into a single layer on a winding frame.Then, the shrinkage rate of the linear material was 5%.
Reduce the circumference of the winding frame so that
After drying, the product was dried by heating and then cut to obtain a 1200 denier viscose rayon linear product, which was designated as Example 1. The linear material, which had been wound around the reduced frame periphery before heating and drying, had shrunk to the length of the frame periphery at the end of drying, and was further compressed and dried under tension. Manufacturing conditions for Γ Example 2 Example 2 was manufactured under the same conditions as Example 1, except that the shrinkage rate of the linear material was changed to 12%. Production Conditions for Γ Comparative Examples 1 and 2 A 1200 denier viscose rayon linear product was produced according to the method of the present invention in Example 1, with the shrinkage rate of the linear product being changed as follows. Comparative Example 1 Yarn shrinkage rate: 0% Comparative Example 2 Yarn shrinkage rate: 17% Manufacturing conditions for Comparative Example 3 Manufactured under the same conditions as Example 1 except that the linear material was stretched by 15% in the spinning process before washing. did. Obtained Examples 1 and 2 and Comparative Examples 1, 2, and 3
The performance of each linear material is shown in Table 1.

[Table] As is clear from Table 1, the linear material of Example 1 obtained by the method of the present invention had a toughness of 41 g/
dx%, knot strength and elongation of 15g/dx%, loop strength and elongation product of 1.8g/dx%, and also good straightness, making it an excellent viscose rayon linear product. There is. Regarding Example 2, toughness 45g/d×%,
Knot strength elongation product 20g/d×%, loop strength elongation product 2.5
g/d×%, which shows extremely excellent physical properties, and the product has satisfactory straightness as a linear product. The product of Comparative Example 1, which was subjected to heat drying without reducing the circumference of the winding frame to prevent the linear material from shrinking under no tension, had excellent straightness but lacked toughness. 28g/d×%, knot strength elongation product 3.6g/d×%, loop strength elongation product 0.5g/d×
%, which is inferior in physical properties compared to the product of the present invention. In Comparative Example 2, the shrinkage rate of the linear material was 17%.
Although the toughness of this product is 39 g/d×%, which is inferior to the product of the present invention, the knot strength/elongation product and the loop strength/elongation product are 21 g/d×% and 2.6, respectively.
g/d×%, which is equivalent to or exceeds the product of the present invention. However, this product has poor straightness and is difficult to use as a polishing brush. Regarding Comparative Example 3, the drawing rate was
It was 15%. The toughness at this time is 17g/d×%,
The knot strength/elongation product was 1.1 g/d×%, and the loop strength/elongation product was 0.2 g/d×%. Although this product has excellent straightness, its physical properties are significantly inferior to the products of the present invention. Example 3 and Comparative Example 4 Γ Manufacturing conditions for Example 3 A 2000 denier viscose rayon linear product was manufactured under the same conditions as Example 1 except that the spinneret was changed to 1.3 mmφ x 1 ^H. . Manufacturing conditions for Γ Comparative Example 4 A viscose rayon linear product of 8000 denier was manufactured under the same conditions as in Example 1, except that the spinneret was changed to 1.5 mmφ×1 ^H. The performance of the obtained linear products of Example 3 and Comparative Example 4 is shown in Table 2.

[Table] From Table 2, the linear product of Example 3 obtained by the method of the present invention has a toughness of 40 g/dx%, a knot strength and elongation of 16 g/dx%, and a loop strength and elongation product of 1.7 g/d. ×%
It is an excellent viscose rayon linear product with good physical properties and good straightness. Although Comparative Example 4 was manufactured under the same conditions as Example 1 except that the denier was as large as 8000, the toughness was 24 g/d×%, the knot strength elongation product was 95 g/d×%, and the loop strength was Elongation product 0.9g/d×%
A significant decrease in physical properties was observed compared to the product of the present invention. <Effects of the Invention> Since the present invention is configured as described above, the viscose rayon linear product of the present invention essentially has excellent heat resistance and organic solvent resistance, and is also excellent in durability. . As a result, a viscose rayon linear material that can be used as an abrasive brush suitable for precision machining and finishing is provided.

Claims (1)

[Claims] 1. The stress peak temperature in the heat shrinkage stress curve is
Single yarn 300~ characterized by exhibiting a temperature of 180~200℃
5000 denier viscose rayon filament. 2. A single yarn characterized in that a filament obtained without stretching in the spinning process is washed and then shrunk by 3 to 15% in the drying process without applying tension, and then dried at a fixed length. A method for manufacturing 300-5000 denier viscose rayon filaments. 3. In the drying process, the linear material after washing is rolled up in one to several layers on a winding frame, and then the linear material is wrapped in a winding frame so that the shrinkage rate of the linear material is 3 to 15%. 3. The method for producing a viscose rayon filament according to claim 2, wherein a heat drying treatment is performed after the circumference is reduced.