JP3034636B2 - Flame retardant cone paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cone paper used for a diaphragm of an electroacoustic transducer such as a speaker, and more particularly to a flame retardant cone paper having flame retardancy.

[0002]

2. Description of the Related Art Generally, most of flame-retardant papers mainly contain inorganic glass fibers, and are often used as building materials such as wallpaper. Recently, carbon fiber paper has also appeared as an electromagnetic shielding paper, but all have low strength as fiber paper, and cannot be used as a cone paper used for a speaker diaphragm in terms of strength. These materials have low properties such as flame retardancy and heat resistance because they use a large amount of hot water reactivated poval fiber (polyvinyl alcohol = PVA) as an organic fiber as a fiber binder. To date, there has been no example of using fiber paper containing a large amount of flame-retardant fiber material as cone paper, and fiber reinforced resin (FR) made of long fibers such as glass fiber, carbon fiber, and aromatic polyamide fiber (Kevlar) as woven fabric
P) Only cone paper is present. FRP cone paper is impregnated with a large amount of resin (epoxy, unsaturated polyester resin), so it is heavier than the above fiber paper, heat resistance,
Properties such as flame retardancy are inferior, the production process is long, processability is inferior, and fiber materials are expensive. In particular, carbon fiber reinforced resin (CFRP) using carbon fiber or carbon fiber paper is even conductive, and cone paper requires special insulation treatment or the like.

[0003] There have been studies using organic high-elastic fibers such as aromatic polyamide and imide fibers having high elasticity for fiber paper (insulating paper). The index (Limited Oxygen Index) is lower than chlorinated fiber, and the properties of the fiber paper are the same as above,
It is also expensive. The strength of the fiber paper does not greatly differ from that of the fiber paper mainly composed of inorganic fibers, and does not reach the strength of general cellulose fibers (wood pulp paper).

[0004] There are few chlorine-based fibers having high flame retardancy per se as flame-retardant paper, and there is no example of use in corn paper. The reason for this is that PVA fiber must be used as a fiber binder, and in the cone paper manufacturing process using the press drying method, mold contamination during drying becomes severe. Conventionally, a method often used for flame-retardant cone paper is to impregnate cellulose fiber paper cone paper with an inorganic phosphate-based flame retardant,
Most cases are flame retardant. However, paper containing such solids is brittle, weak, has little durability against vibrations that are repeatedly subjected to repeated stress, and may break during vibration.

[0005]

There are several methods for producing a paper-like substance using chlorine-based synthetic fiber short fibers having excellent flame retardancy. One method that can be easily conceived is to mix with wood pulp. There is a method in which the paper is made into paper, and a method in which a fibrous heat-reactivated polyvinyl alcohol fiber (PVA = Poval fiber) is used. However, the latter, in particular, is used as a fiber binder for many synthetic (inorganic, organic) fiber papers other than chlorinated fibers, but needs to be added in large amounts to increase the strength of the paper. It is difficult to obtain flame retardant performance. Recently, flame retardant poval fiber has been used as a papermaking fiber, but not only does it not provide high strength, but also uses an organic bromine compound as a flame retardant, raising concerns about the dioxin problem.

[0006] Even a general papermaking company has a problem of contamination due to dissolution of poval fiber in a papermaking net (wire) at the time of papermaking at a factory, a dryer at the time of drying, or felts, etc., and has not been sufficiently solved. In addition, even in the production of corn paper, since the press drying method (press drying method) is adopted for drying, the contamination and adhesion by the dissolved poval (fiber, powder) to the paper making net, press mold, etc. Difficult to manufacture. In order to achieve the maximum strength of fiber paper using Poval fiber, there is an optimum condition between the water content in the web (composite fiber and water) and the thermal reactivation temperature. It is narrow and difficult to manage with tolerances of about ± 5% each, and reproducibility is poor. From the above, when PVA fiber is considered as a binder for chlorine-based fiber paper, it becomes very difficult from the viewpoint of flame retardancy, production control and the like.

[0007] The present invention has been made in view of the above points, and an object thereof is to provide a high elastic modulus, high strength, heat-resistant, flame-retardant chlorine-based fiber and a fibrous material. An object of the present invention is to provide a flame-retardant cone paper suitable for mass production by increasing the contact area and increasing the strength of the paper-like matrix.

[0008]

In order to achieve the above object, the flame-retardant corn paper of the present invention comprises aromatic polyamide fiber as a fibrous binder to chlorine-based staple fibers having high flame retardancy. Ultra-beaten pulp obtained by ultra-beaten fibrillated fibers and cellulosic fibers, and made with a normal paper machine, has flame retardancy, humidity resistance and water resistance, high strength, high elastic modulus, high internal It is characterized by having loss.

Further, in order to achieve the above object, the flame-retardant cone paper of the present invention has the flame-retardant cone paper described above with further improved flame retardancy, heat resistance, water resistance and humidity resistance. It is characterized by impregnating or coating with a solution of an aromatic polyamide, an imide compound, an organometallic polymer compound, an inorganic compound (silicate compound) or the like in order to obtain a high strength, a high elastic modulus and a high internal loss.

[0010]

[Function] Synthetic fibers such as chlorine fibers are different from cellulose fibers in that the surface of the fibers is non-hydrophilic, the specific surface area is small, and the contact area between fibers is not increased by plasticization with water. The surface tension of water does not work. Therefore, a strong web cannot be formed, and the strength of the fiber paper is weak and the utility is poor. The strength of the paper-like matrix is related to the density, and generally, the higher the density, the higher the strength. The strength of the fiber paper depends on how to increase the density of the paper-like matrix. This method of increasing the density is achieved by using short fibers and filling between relatively long fibers (cut fibers). The short fibers include milled fibers and fibrillated fibers. If these are hydrophilic fibers such as cellulose fibers, the web strength and the fiber paper strength can be easily increased.

[0011] A fibrillated fiber (also called fibrit fiber) produced by dissolving a meta-aromatic polyamide fiber material in a solvent and jetting it into a non-solvent, or ultra-beaten wood obtained by mechanically super-beaten wood pulp Pulp also has a large specific surface area, especially the latter having a specific surface area of 10.0 m ² / g or more, and up to 200 m ² / g by mechanical operation. Therefore it is most suitable for increasing the density of the paper. In addition, the surface of the fiber is hydrophilic, the surface tension of water acts between the fibers, hydrogen bonding is established, and the web strength and fiber paper strength can be greatly increased. In addition, ultra-beaten wood pulp has a very large specific surface area, so it has excellent dispersing performance and reduces the sedimentation speed of high density chlorine-based fibers (1.32 to 1.70 g / cm ³ ) in water to produce uniform fiber paper. give.

In order to improve the mechanical properties and the chemical properties such as heat resistance, water resistance and humidity resistance of these fiber papers, inorganic compounds (silicate compounds), aromatic polyamides, imide compounds, organometallic polymers, etc. By impregnating and coating a solution of a substance such as a compound, these necessary properties are further improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, chlorine-based fibers, which are the most flame-retardant among synthetic fibers, are cut into 0.5 to 10.0 mm into short fibers, and aromatic polyamide fibers are dissolved in a fibrous binder in a solvent. Then, 0.5 to 50% of fibrillated fibers or wood pulp produced by rapid spraying (jet spraying) into a non-solvent is mechanically super-beaten to obtain a specific surface area of 10.
0.5 to 30% of ultra-beaten wood pulp (microfiber) adjusted to 0 m ² / g is added, sufficiently stirred to form a slurry, a predetermined amount of a papermaking chemical is added, and papermaking is performed using a normal paper machine. Press-dried corn paper with flame retardancy, humidity resistance and water resistance, high strength, high elastic modulus and high internal loss. Since this ultra-beaten pulp is not soluble in hot water, there is no contamination to the paper net and the press mold.

Further, if necessary, aromatic polyamides, imide compounds, organic compounds, etc. may be used to improve mechanical properties such as strength and elastic modulus, and to increase chemical properties such as heat resistance, flame retardancy, water resistance and humidity resistance. It can be impregnated and coated with a metal compound, an inorganic compound (silicate compound) or the like. In addition, vinylidene chloride fiber "Saran", vinyl chloride fiber "Tevilon", and their copolymer, vinyl chloride vinylidene fiber "Crehalon", have a lower melting point than other chlorine-based fibers. Can be improved.

Next, the fiber material and the impregnating agent used in the present invention will be described. The figures in parentheses indicate the limiting oxygen index, which is the catalog value of the manufacturer. The value of self-extinguishing property (UL94 standard V = 0 or more) is 25 or more, and therefore LOI 2
The fiber paper can be made into a flame-retardant fiber paper by using five or more fibers. Flame-retardant chlorine-based fiber Fiber name Manufacturer and trade name (Limited oxygen index LOI) 1. Acrylonitrile-salt-based fiber (Mota-acrylic fiber) Kanebo Kanecaron S (28-32) 2. Acrylonitrile-salt-based chloride Kanecaron SR (28-32) 3. Polyvinyl alcohol-salt fiber (polychlor fiber) Kojito Coteran (32-34) 4. Salt salt-vinyl chloride fiber (PVC-PVD fiber) Kureha Chemical Kurehalon (37) 5. Hydrated chloride fiber (PVD fiber) Asahi Kasei "Saran" (56) 6. Salted fiber (PVC fiber) Teijin Tejiron (40)

As the flame-retardant and heat-resistant impregnating agent, the following resins and compounds having flame-retardant and heat-resistant properties are dissolved in respective solvents, and impregnated and coated on cone paper.
Various properties such as heat resistance, flame retardancy, water resistance, and humidity resistance can be improved to high performance.

A. Aromatic polyamide and imide compounds Pressed and dried corn paper is impregnated with the following resin solution, and the polyamic acid-type compound is cured at a high temperature. Representative product names and manufacturing companies are noted. Each of them has flame retardancy, and the heat resistance of polyimide is the highest, and the order of polyamide imide, polyamide and polyester imide is as follows.

Compound name Manufacturer and trade name 1. Aromatic polyamide compound Unitika “Apier Varnish” 2. Aromatic polyimide compound Toray “Trenez”, Dupont “Pile”, Mitsubishi Gas Chemical “BT resin” 3. Aromatic polyamide Imide compounds Hitachi Chemical "HI-400", Sumitomo Electric "Sumitherm", Amuco "Amco AI-10" 4. Aromatic polyimide compounds Sumitomo Electric "Sumitherm F-555", Dainichi Seika "Telebec" 5.Aroma Aromatic polyester amide imide compound Westinghouse “Omega” 6. Aromatic polyhydatoin compound Sumitomo Bayer “Resirm PH-10” 7. Aromatic benzimidazole compound 8. Aromatic polybenzothiazole compound 9. Aromatic polypyromellitic imide compound 10. Silicone polyimide compound Shin-Etsu Chemical "JKR-651" 11. Polyparabanic acid compound Tonen Rack "

B. Organometallic polymer compound An organometallic compound is a structure in which silicon is contained in a main chain bond and carbon, nitrogen, titanium, and boron elements are combined with each other. The components are increased and are ceramicized (metal oxide) to provide heat resistance and flame retardancy.

Compound name Main chain structure Manufacturer and trade name 1. Organic silicon-containing compound a. Polysilane -Si-Si- Silicone oil, silicone rubber, each company b. Polycarbosilane -Si-C- Nippon Carbon "Nicarocoat" C . metal Arukokisshido compounds _{M (OR) n, M =} Ti, Si, Zr, Zn.R = -C n H 2n + 1 Si- (OC 2 H 5) 4, Ti- (OC 2 H 5) 4 , etc. The compound having a small amount of R and C is hydrolyzed in the air to form amorphous ceramics SiO ₂ and TiO ₂ , and has a heat resistance of 400 ° C. or more. Nippon Synthetic Rubber, Catalyst Chemicals, Nippon Soda 2. Organic Boron-Containing, Silicon Compound Borosiloxane -BO-Si- Showa Densen, "Borosiloxane" 3. Organic Titanium-Containing Silicon Compound Polytitanocarbosilane -Ti-Si- OC- Ube Industries "Titanocoat" 4. Organic nitrogen-containing, silicon compound polysilazane -N = Si (R) Tonen "Polysilazane" 5. Organic aluminum-containing, silicon compound polyaluminoxane -Al-O- Sumitomo Chemical 6. Organic fusophazene compound- N = P (OR) ₂ -Idemitsu Petrochemical, Dainichi Seika 7.Organosol a.Alumina sol b.Silica sol

C. Inorganic compound Silicate compound Sodium, potassium, lithium salt, (Na, K, Li) ₂ Si
O ₃ primary reagent, especially lithium silicate (Li ₂ SiO ₃ , Li ₂
(O / SiO ₂ = 7.2-7.8 mol ratio), dried after impregnation, does not dissolve again in water, improves water resistance and humidity resistance, and has no loss on heating up to 1000 ° C.

The surface of the fibers has poor wettability with water,
Even if it is put into the water as it is, it does not blend with the water and floats on the water surface, and air bubbles easily adhere to the fiber surface, so that most of the fibers gather near the water surface as the stirring progresses. To prevent this, add a surfactant and a defoamer to each 10
Add about 0 PPM to make a uniform slurry. This is made into a uniform fiber paper by papermaking. Moisture resistance and water resistance reduced by the addition of ultra-beaten wood pulp are improved by chemicals for papermaking.

1. Method for measuring physical properties Tensile strength: Calculated from the breaking strength of a tensile tester Tensile modulus: Stress-strain curve (SS-Curve) of a tensile tester
Calculated from 0.25% modulus of JIS K-7213 1. Internal loss: Calculated from a torsional free damping type viscoelasticity tester. Flame retardancy test method According to JIS D 1201 "Test method for flammability of organic materials for automobile interiors".

Example 1 Kanecaron S (Modacrylic fiber, Kanebo), Kanecaron SR (Modacrylic fiber, Kanebo), Cordelaan (Polyclar fiber, Kokijin), Krehalon (P)
VC-PVD fiber, Kureha Chemical), Saran (PVD fiber,
(Asahi Kasei), Tevilon (PVC fiber, Teijin) and the like are cut into 3 mm, and as a fibrous binder, fibrillated fiber of aromatic polyamide fiber is added in an amount of 0.5 to 50%.
0.5-3 ultra-beaten wood pulp (microfiber)
Add 0%, make a 3% slurry with water, and disintegrate by sufficiently stirring for 10 minutes with a disintegrator. A predetermined amount of a papermaking chemical is added thereto, and the papermaking is performed using an ordinary paper machine, followed by press drying to obtain speaker cone paper. At the time of papermaking, a surfactant and an antifoaming agent are added at 100 PPM in order to remove fiber wetting and air bubbles.

A. The following are used as the fiber material. Chlorine fiber 3mm cut 80
Part Aromatic polyamide fiber Fibrillated fiber 20
Part ultra-beaten wood pulp microfiber 10
Part b. The following papermaking chemicals are used: Wet strength improver Epoxy polyamide resin 1.5
Part Size Dimer acid ester 0.5
Part surfactant anionic 100
PPM defoamer silicone 100
PPM c. Physical properties and performance obtained are as follows. Attached Table 1
It is shown in "Flame-retardant cone paper Example-1 Physical properties and performance Flame-retardant cone paper-3". d. Results of Flame Retardancy Test Test Method According to JIS D 1201 "Test Method for Flame Retardancy of Automotive Interior Organic Materials", all the chlorine-based fiber papers were self-extinguishing below the marked line.

Example 2 The corn paper prepared above was impregnated with a solution of the following substances to further improve mechanical properties such as strength and elastic modulus, flame retardancy, heat resistance and water resistance. And chemical performance such as humidity resistance is improved.

1. Aromatic Polyamide, Imide Compound Aromatic Polyamide Resin Flame Retardant Heat Resistant High Strength High Elastic Modulus Aromatic Polyamideimide Resin 〃 〃 芳香 ポ リ エ ス テ ル ポ リ エ ス テ ル ポ リ エ ス テ ル ポ リ エ ス テ ル 樹脂〃 〃 〃 〃 Silicone polyimide resin 〃 〃 〃 〃 Polyparabanic acid resin 〃 〃 〃 芳香 Aromatic polyimide resin 〃 〃 〃 〃

2. Organometallic polymer compound Organic silicon-containing compound Heat resistance Flame retardant High elastic modulus Organic containing boron, silicon compound 化合物 〃 Organic titanium containing, silicon compound 〃 〃 Organic aluminoxane compound 〃 〃 Organic phosphazene compound 〃 〃 〃

3. Inorganic compounds Alkali metal silicates (sodium, potassium, lithium salts) Heat resistance Flame retardancy High elastic modulus Polyaluminoxane ア ル ミ 〃 Organosol Alumina sol Excellent weather resistance. The physical properties after impregnation are shown in a separate table together with the above results.

[0030]

As described above, according to the present invention, papermaking is performed by adding, as a fibrous binder, fibrillated aromatic polyamide fibers and pulp obtained by ultrabeating cellulose-based fibers to short fibers of chlorine-based fibers. And press-dried to make cone paper, so it has excellent physical properties such as high elastic modulus and high internal loss, and has excellent flame resistance, heat resistance, humidity resistance, and water resistance. You can get paper.

Further, since the above-mentioned materials are impregnated or coated with an aromatic polyamide, an imide-based compound, an organometallic polymer compound or an inorganic compound to improve properties, physical properties such as high elastic modulus and high internal loss are obtained. And a cone paper having excellent flame retardancy, heat resistance, moisture resistance, and water resistance and excellent in mass production.

Claims (2)

(57) [Claims] 1. A papermaking method comprising adding, as a fibrous binder, a fibrillated aromatic polyamide fiber and an ultra-beaten pulp obtained by ultra-beaten cellulose-based fibers to short fibers of chlorine-based fibers having high flame retardancy. Flame-retardant corn paper which has flame retardancy, humidity resistance, and water resistance, and has high strength, high elastic modulus, and high internal loss. 2. The flame-retardant cone paper according to claim 1, wherein the flame retardancy, heat resistance, water resistance, and humidity resistance are further improved, and high strength, high elastic modulus, and high internal loss are obtained. Flame-retardant corn paper characterized by being impregnated or coated with a solution of an aromatic polyamide, an imide compound, an organometallic polymer compound, an inorganic compound (silicate compound), or the like.