JPS5873312A - Bristle for paint brush - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to bristles for paint brushes that are light and flexible due to their low bulk specific gravity, in addition to being easy to process the tip.

Natural goat hair, pig hair, horse hair, etc. have been used as bristles for paint brushes for a long time, but in recent years, synthetic fibers have also been widely used. Synthetic fiber bristles for paint brushes have many advantages such as quality and stability of supply, and their quantity and uses are expanding rapidly.

Bristles for paint brushes made of synthetic fibers have a tapered shape (cheebird) and tip processing (split tip processing) to maintain paint content, applicability, and elasticity during painting comparable to those of natural products. Various cross-sectional shapes such as cross, quatrefoil, gear, circular hollow, and multi-hole hollow are used.

As for the cross-sectional shape, a modified cross shape or a four-lobed shape with a lip is practically advantageous because it has a large amount of paint and is easy to split. Certain hollow shapes are also useful.

As a result of research into bristles for paint brushes that have a hollow shape and bulkiness without impairing the splitting properties of the ribbed shape, the present inventors found that by bringing the tips of the ribs into contact with each other, the cross section of the bristles can be improved. It was discovered that the shaped bristles have the above performance.

That is, the present invention provides fibers made of thermoplastic polymers,
Its cross section is composed of a plurality of thick conical protrusions arranged radially from the center, and each protrusion tip is in substantial contact with the protrusion tips on both sides, resulting in a plurality of hollow shapes. The content includes bristles for a paintbrush characterized by the following:

It is preferable that the thick tip-shaped protrusion is mushroom-shaped or T-shaped, and it is more preferable that the area of the hollow portion in the cross-sectional view is about 20 to 60% of the cross-sectional area formed by the outer periphery. The number of cross-sectional voids in the hollow shaped part is preferably in the range of 3 to 6. Further, it is preferable that the fiber has a thick and thin portion in the axial direction, and the ratio of the diameter of the root of the thick portion to the diameter of the tip is in the range of 1.3 to 4.0.

The thermoplastic resin used in the present invention can generally be used as long as it has fiber-forming properties, and examples thereof include polyester, nylon, polysulfone, and acrylonitrile-containing resins known as acrylic and modacrylic fiber raw materials. Among them, considering water resistance and moderate abrasion resistance as a paint brush, 40% by weight or more,
Acrylonitrile-containing resins containing preferably 80% by weight or less of acrylonitrile and 60% by weight or less, preferably 20% by weight or more of vinyl chloride and/or vinylidene chloride are suitable.

Further, the present invention will be explained in detail using figures.

Figure 1 (a), (b), and (c) are examples of so-called ribbed cross-sectional shapes, in which the space surrounded by the ribs is retained within the fiber bundle. This improves the paint retention, and the most noticeable effect is that the protruding ribs are easily separated and divided into several bristles.

Usually, it is obtained by dividing the ribs at the tip of the bristles after being assembled to the metal fitting of a paint brush, or by exposing the bristles in the form of raw bristles to a rotating needle cloth or abrasive sand. Such tip processing is an essential element for increasing paint content and application uniformity and improving the performance of the paint brush.

On the other hand, a hollow cross-sectional shape as shown in Figure 1 (ω(b) and (c)) can provide a light and flexible paint brush with a small bulk density.
Since the fiber surface is smoother than the ribbed cross-section shown in 1(d), (e), and (f), the tip is less likely to be split with cloth or abrasive sand when processing the tip as described above, which improves work efficiency. will drop significantly.

By improving the ribbed cross-sectional shape, the present inventors have achieved the present invention, which has a cross-sectional shape that has the same bulkiness as a hollow cross-section yarn and does not reduce the efficiency of tip processing. That is, as shown in Figures 2(a) and 2(b), the rib tips are substantially in contact with each other so that the outer periphery is closed, and the ribs are wrapped inside and have an independent gap. It is something to do. During normal manufacturing, the tips of the ribs are slightly fused to each other, but if you look at the cross section, you can see that the shape of the tips before being fused can be recognized.

Further, the tips of the ribs do not necessarily need to be in contact or lightly fused at all parts, and even if there is a slight gap, the effects of the present invention can be achieved to some extent. In the present invention, "substantially in contact" means this.

To explain the present invention in more detail, fibers made of a thermoplastic polymer in the range of 50d to 1500 (1), which are practically used as bristles, have a cross-sectional shape of 7-shaped or 6-6 radially mushroom-like protrusions. consisting of a combination of shapes),
By bringing the tips of the outer peripheral portions into contact with adjacent tips, three to six void portions surrounded by the multiple connected outer peripheral portions and internal partition wall portions are formed. Desirably, the total area of this void portion is 20 to 60% of the total cross-sectional area comprising the outer periphery.
By doing so, it is possible to maintain bulkiness equivalent to that of a porous hollow fiber as exemplified in Figure 1cc). In this way, it is possible to obtain the same bulkiness as a hollow cross section despite having a rib shape.

In addition, since the contact area on the outer periphery of the cross-sectional shape of the present invention is a mere contact or a light adhesion caused by an oil agent, the contact area opens due to impact during the tip processing mentioned above, and the cloth and abrasive sand are trapped inside. Since it can be easily divided into sections, it is possible to maintain processing efficiency equivalent to that of the rib-shaped cross section illustrated in FIGS. As described above, the present invention is characterized in that it is possible to maintain the same bulkiness and surface smoothness as a hollow cross section while maintaining processing efficiency equivalent to that of a rib-shaped cross section.

The present invention is obtained by extruding a spinning dope in which a thermoplastic polymer is dissolved in a solvent into a coagulation bath through a nozzle hole to form fibers, followed by drying and stretching. It can also be manufactured by melting and extruding a thermoplastic polymer and cooling it; however, the former method, which solidifies quickly, is stable and advantageous in order to maintain the contact area without fusing.

In order to obtain the cross-sectional shape of the present invention, the nozzle hole shape illustrated in FIG. 3 is used. A predetermined shape can be easily formed by adjusting the ratio between the discharge speed and the take-up speed of the polymer or polymer solution during spinning, that is, the draft coefficient. With low draft and raft, a cross section with a relatively large contact area as shown in Figure 2(a) can be obtained, and with high draft, a cross section with a small contact area similar to the nozzle hole shape shown in Figure 2(b) can be obtained. . This takes advantage of the ballast effect near the nozzle hole. Furthermore, if the draft coefficient is increased above the limit, the contact surfaces will separate, making it impossible to obtain the effects of the present invention, so it is necessary to perform spinning at a draft below this limit. Conditions for adjusting the contact area vary depending on the size of the cut width (D) on the outer periphery of the nozzle, the viscosity of the polymer or polymer solution, the spinning speed, etc., as shown in Figure 3.
Easy to adjust with draft coefficient.

The appropriate number of T-shaped lips constituting the cross-sectional shape of the present invention is 3 to 6. If the number is less than 2, it will be susceptible to bending and deformation due to external force, and if it is 7 or more, the bulking effect will be small. There is no. Further, the ratio of the thickness of the outer circumferential portion constituting the cross section of the present invention to the internal partition wall portion is preferably 1:1 to 2:1 from the viewpoint of strength against external forces.

Example A copolymer consisting of 50% by weight of acrylonitrile and 50% by weight of vinyl chloride was dissolved in acetone to prepare a spinning dope (viscosity: 50 poise) having a concentration of 30% by weight. As a spinneret, the hole shape is similar to that shown in Figure 3, and the cut width l = 0.0.
A material with a weight of 9 mg and a pore diameter equivalent to 1.0 mm in diameter was used and spun into an aqueous coagulation bath containing 30% acetone. A sample (A1) with a large contact area similar to that shown in FIG. 1(a) was obtained with a draft coefficient in the range of 0.4 to 07. Further, in the draft coefficient range of 09 to 1.3, a sample (black 2) with a small contact area similar to that shown in FIG. 2(b) was obtained. A comparative example sample (A3
) was obtained. The sample was dried at 120°C, stretched three times at 125°C, and further heat-set at 150°C for 120 seconds.

The obtained sample has a fineness of 550 denier and an outer diameter of 320.
It was ~400μ.

When the bulk specific gravity of the fiber bundles of the obtained samples was measured, A1 was 070, A2 was 063, Shima 3 was 085, and A
1 and /FFx2 are especially bulky compared to Tora 3. The bulk specific gravity of the conventionally known rib-shaped one is 08-09, and the bulk specific gravity of the hollow-shaped one is 06-07.

In addition, the tip of the resulting sample bundle was processed using a rotating body wrapped in clothing. A1. The same split shape was obtained for A2゜Black 3 with the same processing time, and Sake 1 and A2 were A3.
It became clear that there was no difference in the shape of the ribs.

[Brief explanation of drawings]

Figure 1 shows the cross-sectional shapes of conventional paint brush bristles, (a) (o) (a) are hollow ones (d) (e
)(f) is an example of a ribbed shape. FIG. 2 shows a cross-sectional shape illustrating the bristles of the present invention.
) is an example in which the contact area of Lip is large, and (b) is an example in which Id is small. FIG. 3 is a plan view of the nozzle hole shape used in the present invention. Patent applicant Makoto Asano, patent attorney representing Kanebuchi Chemical Industry Co., Ltd. Figure 1 (a) (b) (C) (d
) (e) (f) Figure-2 (a) (b) Figure-3

Claims (6)

[Claims] (1) A fiber made of a thermoplastic polymer, whose cross section is composed of a plurality of tapered protrusions arranged radially from the center, and the tips of each protrusion are in substantial contact with the tips of the protrusions on both sides. A bristle for a paintbrush, characterized in that it exhibits a plurality of hollow shapes. (2) *The bristles according to claim 1, wherein the fibers have a large narrow portion in the axial direction. (3) The bristles according to claim 1, wherein the thick tip is mushroom-shaped or T-shaped. (4) The bristles according to claim 1, wherein the area of the hollow portion is approximately 20 to 60% of the cross-sectional area formed by the outer periphery in the cross-sectional view. (5) The bristles according to claim 1, which have 3 to 6 hollow shaped portions. (6) The bristles according to claim 1, wherein the bristles are processed and the bristles are segmented.