KR800000565B1 - Treatment of material with silicon halides - Google Patents

Abstract

A method of preparing waterproof materials by treating materials with silicon halides was described. The waterproof materials having degradation preventive properties against acids were prepd. by jet-injecting silicon halides vapor to a treatment room through which materials pass, and by keeping a state of the vapor turbulent.

Description

Waterproofing method by silicon halide

Figure 1a is a process schematic of the prior art using laminar flow of silicon halides

Figure 1b is a schematic diagram of the material treatment of the present invention using non-laminar flow of silicon halides.

FIG. 2a is a view of the processing apparatus for creating and maintaining a non-laminar flow as in FIG. 1b.

Figure 2b shows the degree of hardness of the branching pipe for treatment

FIG. 3a is a graph showing the correlation between silicon halides and by-product hydrogen chloride in FIG. 2a.

3b is a graph showing the correlation between water resistance and deterioration in a processing apparatus.

Figure 3c is a graph showing the correlation between the pressure and the length in Figure 2a

4 is a triangular coordinate of the blendable range of the waterproofing silane mixture of the present invention.

The present invention relates to a method of treating a silicon halide material to obtain a waterproof material that is free from degradation by acid.

It is well known that it is useful for waterproofing silicon halides.

References: US Patents 230622 (1942), 2386259 (1945), 2412470 (1946), but no methods have yet been industrialized.

Halides react with hydroxyl groups in the presence of moisture to form a film on the surface of the material to be treated to enhance the waterproofing effect.

Hydrogen chloride gas is generated as a by-product at this time, but this hydrogen chloride gas can also react with moisture in the treatment of the substance. The resulting hydrochloric acid, in particular, attacks and degrades cellulosic material. If the material to be treated contains even a small amount of water, this means the presence of hydrochloric acid and this phenomenon is accompanied by more detrimental action if the material is porous or hygroscopic.

In order to eliminate such harmful effects, for example, there is a method of neutralizing and removing hydrochloric acid using ammonia. Reference: US Pat. No. 2,306,222, but such an operation is not suitable for some applications, especially the paper industry, as it requires a liquid bath as well as the complexity of neutralization.

This can be easily understood from US Patent No. 2824778 (1958), which states, "There is no economic or technical way to increase the waterproofing of fibers in any process." In order to solve the above problems, U.S. Patent No. 2,284,778 is a weak alkali for neutralizing acidic reaction by-products after the reaction conditions are prepared so that a cellulose-based substance is a mixed gas of silane and an inert gas, so that side reactions that cause deterioration do not occur. The method of immersion in water is described.

Neutralization conditions at this time are described in US Pat. No. 2,995,470 (1961). It describes how the aerosol vapor of the treatment agent moves from bottom to top in the reaction zone.

The above patent describes the use of a spray nozzle to move the silane mixture upwards.

Water treatment effect after the operation was enhanced, but the pH value is 3 or less, which is far from the neutralization value of 7, and as a result, the reaction is accompanied by unnecessary acid decomposition. have.

In addition to the above patents, Canadian Patent No. 906,849 (1972) states that "Cellulose must be neutralized by immersion in alkaline aqueous solution immediately after treatment with halides." In order to eliminate such degradation by hydrochloric acid by-products, a method of contacting silicon halide vapor with a substance in the presence of the vapor pressure of an inert solvent is required. Such inert solvents are described in detail in US Pat. No. 3,856,558 (1974).

The results of the experiment according to the aforementioned Canadian patent method are as follows. Yellow kraft paper with a moisture content of 7.99% is heated at 300 ° F. for about 3 seconds to bring about 5% moisture content. The preheated and dried paper is continuously passed through a treatment chamber to which silane vapor is supplied in the presence of toluene as an inert solvent. The composition of the silane vapor at this time is 70% by weight of methyltrichlorosilic acid, 20% by weight of dimethylchlorosilic acid, 10% by weight of dichlorosilane and the weight of this vapor is 1% of the paper weight. Toluene as an inert solvent is 20% by volume or 22% by mole of the total composition supplied to the treatment chamber. The residence time of the paper in the processing chamber atmosphere consisting of about 2% by volume of silane and toluene at room temperature is about 6 seconds. As the paper emerges from the processing chamber, it is blown directly to the radiant heat source to directly blow air to raise the paper surface temperature to about 200 ° F. Some of the resulting material was sampled and tested for water repellency. The treatment was not completely satisfactory. In order for the silane to react sufficiently, it is necessary to fully seal the device to prevent the release of dangerous silane vapors. Tensile strength was not tested.

To date, a great deal of research has been conducted on solvents, but the technicians concluded that the low pH value of the final product makes it difficult to obtain a perfect product.

It also aims to elevate the object of the present invention to an economical level which relates to waterproofing which does not involve deterioration by undesirable acids.

The method of the present invention also relates to the high speed of waterproofing and relates to a method of waterproofing a material at a relatively high pH without the need for neutralization treatment or inert solvent to prevent degradation by acid.

The present invention completes the treatment by introducing the silicon halide vapor into the non-laminar flow through the entire reaction zone to the treated material to maintain the non-laminar flow state, and in order to maintain the non-laminar flow, the Reynolds number (N It is necessary to make _Re ) as high as possible and the degree of turbulence gradually increases as N _Re increases. When the Reynolds number is 1,000 to 2,000 or more, it is non-laminar flow. Otherwise, such non-laminar flow is used to quickly perform waterproofing and to remove the by-product hydrochloric acid vapor.

Previously, when laminar flow was used, the residence time for waterproofing was considerably long, resulting in unnecessary side reactions because the contact time of hydrochloric acid vapor and the treated material was longer than necessary. However, maintaining the non-laminar flow according to the method of the present invention has an advantage that the hydrochloric acid vapor, which is a by-product, can be removed before the side reaction occurs in contact with the treated material due to the rapid waterproofing. Moreover, the reaction time can be further shortened by using nitrogen as a carrier gas as a feature of the present invention.

To obtain the non-laminar flow as described above, a structure having a plurality of small diameter holes and baffles is used, and to maintain such non-laminar flow, a narrow spherical reaction zone is formed and maintained in the treatment section. . In the case of using the method of the present invention, the discharge chamber is kept below atmospheric pressure, and the reaction of silicon halide in the reaction zone is sufficiently performed so that the waterproofing is sufficiently performed, and the reaction of hydrogen chloride which causes deterioration is not sufficiently performed.

Generally the cellulose treatment material contains 2-7% by weight of moisture. The silicon halide vapor containing the lower alkyl silicon halide is brought into contact with the treatment material for about 0.1-8 seconds. Contact steam reacts with water to produce siloxanes. The concentration of silicon halide and the contact temperature are adjusted so that the pH value of the treated material is 2.5 or more and waterproof.

In particular, the moisture content is usually 3.5-6.5%, 4.5-6.5% is good. The contact time ranges from 0.5-4 seconds, preferably 0.5-1.5 seconds.

The present invention will be described in detail with reference to the drawings.

In FIG. 1a, the treatment material 10 is moving in the direction of the arrow and the treatment material is exposed to the vapor 21 flowing in the laminar flow.

In laminar flow, only a few molecules close to the surface to be treated react with the hydroxyl groups in the material to form a siloxane film. When the reaction is initiated, hydrogen chloride represented by dotted line 31 and circle 41 is produced.

Some of the hydrogen chloride moves in the direction of the flow, but most of the hydrogen chloride represented by the circle 41 'remains on the surface of the treated material. Since the flow at this time is a laminar flow, the by-products remain almost on the surface except for the movement corresponding to the amount of diffusion of the gas, thus splitting the surface of the paper.

However, because the flow becomes turbulent in FIG. 1b, which maintains non-laminar flow, the method of the present invention, a sufficient amount of silane mixture is in contact with the surface of the treatment material to allow the reaction to occur more quickly than when treated with laminar flow. In addition, the turbulence at this time is removed from the surface with most of the hydrogen chloride 32, but only a small amount of hydrogen chloride 42 'remains. It should be noted that the first and second a and second b only show the fact that the present invention has economic value compared to the prior art, and the first and second a and b do not limit the scope of the present invention.

Next, see Figure 2a and continue the description. It is shown as the process room temperature 50 and maintains the non-laminar flow (turbulence) by installing an obstacle 51 in the flow of the silicon halide treated steam.

인치가지 가능하며 일반적으로 공간의 폭은

인치 내지

인치로 되어 있으나 1인치가 될 수도 있다.The lower portion 52 and the upper portion 53 of the processing chamber are as close to the processing material 10 as possible. As the 52 and 53 come into close contact with each other, the passage space of the material becomes small to form a narrow passage. The width of the space is minimal for the passage of cellulose material

Inch is possible and generally the width of the space

Inches to

It is in inches but can be one inch.

The treatment material 10 is put through a sealer 60 made of elastic materials 61 and 62 having good warpage, and as a material of the sealer, fluo under the trademark “VITON” manufactured by Dupont- Fluro-elastomeric members are good.

After passing through the sealer 60, the silicon halides coming from lines 73 and 74 in the mixed gas tank are processed through the manifold.

The manifold exhales silicon halide vapor on the treatment material 10 and the manifolds 71 and 72 respectively exhale steam on one side 11 and the other side 12 of the treatment material.

Manifold (71) is a tube of 1 to 1/2 inches in diameter, the tube has 40 holes (75) of 1/16 inches in diameter every inch. Another type of manifold is one having a diameter of 5/8 inch and having 80 holes 75 with a diameter of 3/32 inch at 1 inch intervals. The exhaust steam after treatment comes from two parts of the exhaust section 80. The first discharge portion 81 is kept at a reduced pressure and sent mainly to lines separators 83 and 84. After the treatment material passes through the second hermetic 60 ', which is similar to the first hermetic 60, the ejector exiting the second outlet 82 is discharged via line 85.

N _Re in the processing chamber 50 is 1,000 to 2,000. In general, N _Re is defined as

D of this stage represents the equivalent diameter of the processing chamber 50 or the diameter of the hole 75.

ρ represents the density of the flow

u represents the velocity of the gas passing through the equivalent diameter

μ indicates the viscosity of the gas.

In the conventional technique, N _Re was completely laminar because it was about 10. In addition, the treatment chamber is also quick and easy to remove the hydrogen chloride vapor, which is a problem unlike the conventional one.

On the contrary, in the case of laminar flow, as the treatment time becomes longer, the hydrogen chloride and the treated material relatively cause unnecessary reactions.

Conventionally, since the upflow is used to remove unnecessary halides, it is not possible to process it unless it is a porous material.

Next, in FIG. 3A, curve (a) shows the decrease in the amount of silicon halides according to the passage length of the treatment chamber, and curve (b) shows the amount of hydrogen chloride produced. At the feed point L ₀ the silane mixture starts to react with the treatment material and the residual amount gradually decreases with the passage length of the treatment chamber. Hydrogen chloride, on the other hand, gradually increases with the decrease in silane. The (L ₁ ) position is silane reacted to obtain a sufficient waterproofing effect, but since a large amount of hydrogen chloride is not produced, unnecessary reaction to the treated material does not occur.

Residual silane continues to react with the treatment material even between points (L ₁ ) and (L ₂ ), but at this time, the amount of hydrogen chloride also increases gradually to reach the point (L ₂ ), so that the hydrogen chloride is almost saturated. Make unnecessary reactions Therefore, the length of the process chamber should be defined as the length between (L ₁ ) and (L ₂ ).

After determining the length between points L ₁ and L ₂ , better performance can be obtained by varying the flow of gas mixed with silane vapor. Reducing the total amount of gas injected per unit time further enhances the silane reaction and increases the residence time in the treatment chamber.

3b shows the relationship between waterproof and deterioration. At (L) point ₁ , the waterproofing effect reaches a considerable level, and at point L ₂ , deterioration occurs considerably. Therefore, the length of the treatment chamber should be defined as the length between (L ₁ ) and (L ₂ ) points.

The dashed line in FIG. 3C shows the decrease in pressure along the length of the process chamber. (L ₃ ) denotes the discharge point and the pressure at the point (L ₂ ) is at atmospheric pressure or slightly pressurized (L ₃ ) but drops below atmospheric pressure.

4 shows the effect of the amount of change in the silane component. Each vertex here represents 100% of the component and the opposite side represents 0% of the component.

As shown in FIG. 4, since the R portion is an appropriate range for waterproofing, methyltrichlorosilane (CH ₃ SiCl ₃ ) is less than 70% methyldichlorosilane (CH ₃ SiCl ₂ ) is less than 65% dimethyldichlorosilane: (CH ₃ ) ₂ SiCl ₂ should be kept below 80%.

Although there are some differences depending on the physical properties of each treated material, in the case of paper, the moisture content is 3.5-7.5%, usually 4.5-6.5%. On the contrary, when the moisture is too low, there is a shortage of hydroxyl groups to react with the silane compound. If the water content is excessive, there is a high possibility that the residual hydrogen chloride is converted into hydrochloric acid. Therefore, when using cellulosic materials, the moisture content should be 4-7% and set according to the reaction conditions in the treatment process. In either case, the raw material should be wetted or dried to maintain a constant water content within a predetermined range.

In general, the carrier of the silane mixture is air and its rate should be 150-300 ft / min in a 2 ft silane concentration and 7 ft length treatment chamber. In order to increase the amount of material passing through the treatment chamber, the concentration of the silane mixture in the mixed gas carrier must be increased. Increasing concentrations above 5% creates explosive mixtures in the air. However, this problem is solved by using nitrogen or an inert gas as a carrier to treat at a silane concentration of 20% and a speed of 500ft / min.

Next will be described in more detail through specific embodiments of the present invention.

Example 1

The 25 lb weight of kraft paper was pre-dried to 2.5% by weight of water. The paper thus dried was continuously passed through a process chamber fed with a mixture vapor consisting of 65% by weight methyltrichlorosilane and 20% by weight dimethyl dichlorosilane and 15% by weight of dichlorosilane. The silane reactant was fed at a rate of 2% total paper growth, the paper was passed through the process chamber at a rate of 50 ft / min, at a temperature of 90-91 ° F, and through the air at a rate of 1 ft ³ / min. .

Paper from the treatment chamber was placed in a dryer and treated at 275-300 ° F. The tensile stress of the resulting paper was 21.8 lb / in ^{2, which} was the same as the tensile strength of the untreated paper. In addition, the waterproof value according to DuPont's drop-test for the waterproof effect was 3.5 and the pH value was 6.0.

Example 2

The same conditions as in Example 1 were applied, but the water content was adjusted to 3.9%. The product had a tensile strength of 21 lb / in ² , a waterproof value of 5, and a pH value of 6.0.

Example 3

The same conditions as in Example 1 were applied, but the water content was adjusted to 4.4%. The tensile strength of the product was 21.2 lb / in ² , the waterproof value was 4.5-5, and the pH was lower. A paper of 5.9-6.1 came out.

Example 4

The reaction conditions were the same as in Example 1, but the moisture content was 4.4%, the temperature of the treatment chamber was 83-84.5 ° F., and the air flow rate was 1 ft ³ / min. The paper passing speed was 100ft / min, the paper had a tensile strength of 18lb / in ² , a waterproof value of 4, and a pH of 6.2.

Example 5

The conditions were the same as in Example 4, but the paper passage speed was 150 ft / min. A paper with a tensile strength of 19.6 lb / in ² and a waterproof value of 3.5 was obtained.

Example 6

The conditions were the same as in Example 5, but the paper passing speed was 200 ft / min. A paper with a tensile strength of 20.9 lb / in ² , a waterproof value of 3.0, and a pH value of 6.5 emerged.

Example 7

Thin paper of sulfurous acid bleach having a weight of 11 lbs per area of 3,000 ft ₂ was pre-dried to have a moisture content of about 3.1%. The paper was passed through a treatment chamber supplied with a mixture vapor of 65% methyltrichlorosilane, 20% dimethylchlorosilane and 15% methyldichlorosilane, with the amount of silane being 2% of the paper passage. Set the speed. The paper was fed at a rate of 50 ft / min and the carrier air was fed to the process chamber at a rate of 1 ft ³ / min. The paper was removed from the treatment chamber and dried in a dryer at 275-300 ° F. to obtain the final product. The result was a paper with a tensile strength of 6.4 lb / in ² (same as the first untreated paper) and a waterproofing value of 3.5-4.5.

Example 8

The kraft paper, weighing 34 lbs / 3,000 ft ² , made from kraft paper, was dried to 4% moisture and supplied with a mixed vapor consisting of 65% methylchlorosilane, 20% dimethylchlorosilane and 15% methyldichlorosilane. In the process chamber, 200 ft / min was used, and the carrier air was nitrogen, and 20% of the total amount of the gas was silane vapor. This weight was 6.1% of the paper weight. The paper was removed from the treatment chamber and dried in a drying chamber at 275-300 ° F., yielding a paper with a tensile strength of 91.6% of the original tensile strength and a water resistance of 3-3.5.

Example 9

The conditions were the same as in Example 8 except that the moisture content was 6%, the silane feed amount was 1.7%, and the paper feed rate was 400 ft / min.

Tensile strength was initially 94.6% and waterproof value was 3.

Example 10

The conditions were the same as in Example 8, but the water content was 5%, the silane feed amount was 1.6%, and the paper passing speed was 300 ft / min. The result was a paper with 87.4% of the initial tensile strength and a 3.5-4 waterproof price.

If the conditions similar to the above Example are put, the result of the following Example will come out.

Example 11

Treatment of 42 lb of unbleached kraft paper yields 90% of the original tensile strength and a water resistance of 5.

Example 12

13lb of thin paper is processed to produce 75% of the original tensile strength and 3.5 waterproof.

Example 13

Processing 30 lb of kraft paper results in paper with 81% of the initial tensile strength and a water resistance of 4-4.5.

Example 14

Processing Manila tag stock paper yields a paper that is equal to the initial tensile strength and has a waterproof value of 5.

Example 15

Treatment of brown rolled kraft paper yields papers that reach 95% of their initial tensile strength and have a waterproof value of 5%.

Example 16

Treatment of blue decorative paper yields paper that is equal to the initial tensile strength and has a waterproof value of 4-4.5.

Example 17

Treatment of blue scroll paper yields papers that reach 75% of their initial tensile strength and have a waterproof value of 3-3.5.

Claims (1)

A method of waterproofing a material, characterized by spraying silicon halide vapor into a processing chamber through which the material passes, and maintaining the vapor passing through the processing chamber in a non-laminar flow state, thereby avoiding undesirable deterioration by acid. .

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