JPS6092809A - Continuous manufacture of phenolic foam - Google Patents

Abstract

PURPOSE:To obtain the title foam with uniform thickness and density by a method wherein expansion curable liquid resol type phenolic resin composition is supplied onto an lower belt conveyer so as to be expanded and cured between the lower belt conveyer and an upper belt conveyer under specified conditions. CONSTITUTION:Expansion curable liquid resol type phenolic resin composition 9 is continuously supplied onto a lower belt conveyer 1 and made into contact with an upper belt conveyer 2 before the expansion of said composition starts. The thickness of the expanded layer is gradually increased by blowing pressure while being pressed by a group of hold-down rolls 14-14''' until the predetermined thickness is attained. After that, the expansion and curing of said layer is completed while its thickness being kept uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous method for producing phenolic resin foam.

Phenolic resin foam has excellent heat resistance and fire resistance, and does not emit smoke or toxic gas when burned.
It has attracted attention as a fire-resistant heat insulating material and has come to be widely used in the fields of building materials, furniture, and various industrial materials.

As a continuous production method for phenolic resin foam, two endless belt conveyors 7 installed in parallel in upper and lower stages are continuously rotated in opposite directions at the same (7) speed. A foaming curable liquid resol type phenolic resin composition is continuously supplied onto a belt conveyor and foamed while moving on the belt conveyor, and the upper belt conveyor is brought into contact with the 7-Nol resin composition just before completion of foaming. Continuous manufacturing methods for phenolic resin foams, in which the thickness of the foam is controlled and then cured, are already known (JP-A-Sho!; 2-/37'1-6g and JP-A-3G-11). ,, see Publication No. 1311).

However, in this conventional method, since the upper belt conveyor is brought into contact with the foamable phenolic resin composition immediately before the completion of foaming, there are the following drawbacks.

That is, in general, the supply of the foamed curable phenolic resin composition onto the lower belt conveyor in the conventional continuous production of 7-Nol resin foam involves a reciprocating process across the traveling direction of the belt conveyor to the supply port of the resin composition. The dispersion is caused by exercise,
The resin composition is supplied as a meandering strip on a conveyor belt. However, since the resin composition has poor fluidity, the resin mixture supplied in a meandering band shape does not become a continuous sheet-like product until a certain period of time has elapsed after the supply. Furthermore, even if it is possible to make a continuous sheet by using a method such as smoothing with a comb-shaped distributor, the surface will be uneven and the sheet will have an uneven thickness. It becomes nothing but a thing. A foam obtained by foaming such a discontinuous feed material or a sheet-like feed material with non-uniform thickness has non-uniform density and lacks surface smoothness. Also, if you try to bond other surface materials (for example, paper, cloth, glass fiber fabric, etc.) during foam molding, not only will air bubbles remain on the four parts of the surface and wrinkles will appear on the surface material. This results in poor adhesion between the foam and the surface material.

However, in order to make the above-mentioned meandering strip-shaped feed material remain on the belt conveyor for a sufficient period of time until it becomes a sheet-like product of uniform thickness, the speed of the belt conveyor (forming speed) must be significantly reduced, or Alternatively, the length of the belt conveyor must be significantly increased, and in either case, the productivity of the manufacturing equipment will be significantly reduced.

In addition, just before the foaming of the foamable phenolic resin composition is completed, the surface tackiness of the foamed resin layer has almost completely disappeared, so sufficient adhesive strength can be obtained even when other surface materials are laminated. do not have.

In addition, a skin layer is likely to be formed on the lower surface of the molded foam (i.e., the surface in contact with the lower belt conveyor), but almost no skin layer is formed on the upper surface (i.e., the round surface in contact with the upper belt conveyor). It is not formed. This is because the resin composition is brought into contact with the upper belt conveyor after foaming is almost completed. In addition, the skin layer improves the brittleness that is a drawback of phenolic resin foam, improves the rigidity and strength of the foam, and also contains a low thermal conductivity gas (non-fluorine-containing halogenated carbonized gas) sealed in the cells of the foam. This method is effective in preventing the dissipation of hydrogen, etc.) and keeping the thermal conductivity of the foam low and stable for a long period of time, so it is a method that facilitates the formation of a skin layer for foam manufacturing methods. Whether or not this is the case is extremely important.

Furthermore, since the foam is brought into contact with the upper belt conveyor and pressurized only immediately before the completion of foaming, the bubbles in the formed foam have an elliptical shape with a long axis in the thickness direction, in other words, the shape of the bubbles Since the foam has directionality, the physical properties (for example, compressive strength, bending strength, coefficient of linear expansion, etc.) of the obtained foam also have directionality, which is not preferable.

The present inventor has conducted various studies to improve the deficiencies in the conventional continuous production method of phenolic resin foam, and as a result, the present inventor has arrived at the production method of the present invention.

The first method for continuously producing a phenolic resin foam according to the present invention is to continuously rotate two endless belt conveyors provided in upper and lower stages in opposite directions at the same speed. A foaming curable liquid resol type phenolic resin composition is continuously supplied onto the conveyor, and the upper belt conveyor is brought into contact with the supplied resin composition before foaming starts, and the conveyor is moved while maintaining the contact. The thickness of the foamed layer of the same resin composition is gradually increased by using foaming pressure, and then, after the thickness of the foamed layer of the same resin composition reaches a predetermined thickness, the contact and the thickness are maintained. This method is characterized by completing foaming and curing of the resin composition while moving the resin composition.

The second continuous production method of phenolic resin foam of the present invention is to continuously rotate two endless belt conveyors provided in upper and lower stages in opposite directions at the same speed, A flexible surface material is continuously layered on the surface of at least one of the belt conveyor and the upper belt conveyor, and a foamed curable liquid resol type phenolic resin composition is placed on the lower belt conveyor or the flexible surface material layered thereon. is continuously supplied, and before foaming starts, the supplied resin composition is brought into contact with the upper belt conveyor or a flexible surface material layered thereon, and the foaming pressure is applied while moving the upper belt conveyor while maintaining the contact. The thickness of the foamed layer of the same resin composition is gradually increased, and after the thickness of the foamed layer of the same resin composition reaches a predetermined thickness, the foamed layer of the same resin composition is moved while maintaining the contact and thickness. This method is characterized by completing foaming and curing of the resin composition.

The foam-curable liquid resol type phenolic resin composition of the present invention is a liquid resol type phenolic resin blended with a foaming agent and a curing agent (i.e., a curing catalyst), and more preferably a foam stabilizer is blended. There is.

The curing agent is usually an acid curing agent, such as sulfuric acid,
Hydrochloric acid, phosphoric acid, para-toluenesulfonic acid, xylenesulfonic acid, benzenesulfonic acid, etc. are used. Further, as the blowing agent, hydrocarbons and halogenated hydrocarbons are usually used. Examples include dichlorodifluoromethane, trichlorofluoromethane, butane, petroleum ether, and the like. Further, as the foam stabilizer, for example, silicone oil, dodecylbenzenesulfonic acid, polyalkylene ether polyol, etc. are used.

As is well known, various materials and structures can be used for the upper belt conveyor and the lower belt conveyor in the present invention. Examples of materials for the belt conveyor include fluororesin-coated rubberized cloth, fluororesin-coated stainless steel plate, polypropylene sheet, fluororesin sheet lined with a suitable material, and silicone resin paper.

Examples of the flexible surface material in the present invention include various papers, cloths, glass fiber fabrics, glass fiber nonwoven fabrics, aluminum foils, thin steel plates, and the like.

Next, based on the accompanying drawings showing embodiments of the present invention,
A typical manufacturing method will be explained in detail.

FIG. 7 is a partially cutaway vertical side view of a manufacturing apparatus implementing the first manufacturing method of the present invention, that is, a manufacturing method that does not use a flexible surface material. FIG. 2 is a partially enlarged longitudinal sectional side view of FIG. 1; In FIGS. 7 and 2, / and λ indicate a lower belt conveyor and an upper belt conveyor, respectively, and both belt conveyors rotate at the same speed (linear speed) but in opposite directions. 3 is a mixing tank for a foam-curable liquid resol-type phenolic resin composition; in the same tank 3, a liquid resol-type phenolic resin mixed with a foam stabilizer is placed in pipe 1; Then, the curing agents are continuously supplied from the vibro at predetermined ratios, and these supplies are continuously stirred and mixed by the stirrer 7 to form a foam-curable liquid resol type phenolic resin composition. It is continuously supplied from the supply opening onto the lower belt conveyor/at a predetermined ratio. As is well known, the supply port g makes a reciprocating motion across the traveling direction of the belt conveyor 7, so that the resin composition is supplied as a meandering strip onto the surface of the belt conveyor l.

The supplied serpentine strip-shaped feed material eventually begins to foam naturally at room temperature or by being heated by the heater 16.
However, the lower surface of the upper belt conveyor 2 is brought into contact with the feed, that is, the foamed curable resin composition, before the foaming starting point IO, preferably at a location immediately before the foaming starting point 10. /3 is a nip roll provided for making the contact. By this contact, the resin composition supplied in the meandering band is flattened into a continuous sheet of uniform thickness.

Next, the resin composition, which has become a sheet with a uniform thickness, starts foaming, and the foaming pressure pushes up the lower surface of the upper belt conveyor 2, bringing it into close contact, and the foaming continues while maintaining that contact. It moves along both belt conveyors 7 and λ while gradually increasing the layer thickness. At that time, 0, / ~ 0.7 kt / to the upper belt conveyor 2
The pressure within the embroidery area (foaming pressure) of approximately Ctn'' is controlled to be constantly generated, and preferably to be generated while gradually increasing as the process progresses./4'-/4
'' is a group of presser rolls provided to control the foaming pressure, and the last presser roll /l''' is designed to stop rising when the thickness of the foam layer reaches a predetermined thickness. It is preferable to provide a stopper at the end.The foam // that has been foamed to a predetermined thickness completes its foaming and curing while moving along with the belt conveyors 7 and λ, and the phenolic resin of the product is The foam weighs 7g.

Depending on the composition of the foam-curing liquid resol type phenolic resin composition used in the present invention, foaming and curing can be completed at room temperature without any heating; however, depending on the composition, suitable heating, e.g. jO~
Foaming and curing are promoted by heating to about gOC. In particular, it is desirable to carry out appropriate heating for the purposes of increasing the molding speed, shortening the length of the belt conveyor, and further improving the quality of the product foam. The heater/6 and the heating opening 17 provided in FIGS. 7 and 2 are heating equipment for this purpose.

9. / in Figures 1 and 2 is for adjusting the tension of the upper belt conveyor when the upper belt conveyor is raised or lowered depending on the thickness of the foam to be manufactured. This is a tensile roll used for conveyor belts, and the rolls 2 and 2 can be moved appropriately in the forward and backward directions of the belt conveyor, as shown by arrows 7 and 2'.

Further, /J' is a rising portion provided on both sides of the lower belt conveyor to adjust the shape of both side portions (ear portions) of the foam //.

Next, FIG. 3 is a partially enlarged longitudinal sectional side view of the apparatus in which the second manufacturing method of the present invention, that is, the manufacturing method using a flexible surface material, is carried out. are flexible facings that overlap the surfaces of the lower belt conveyor and the upper belt conveyor, respectively. The structure of the device shown in FIG. 3 is essentially the same as the device shown in FIGS. - or equivalent parts are given the same reference numerals.

In the method shown in FIG. The flexible surface material 2o layered on the surface of the upper belt conveyor 2 is brought into contact with the material, and the phenolic resin foam is then foamed and cured in the same manner as shown in FIGS. 7 and 2. Manufacture. Therefore, the phenolic resin foam obtained by this method is obtained as a foam with a composite structure in which flexible facing materials and 2o are bonded to both the upper and lower surfaces of the foam.

Note that the method shown in FIG. 3 can be changed to a method using only one of the flexible surface material and 2o, as necessary, and the foam obtained by such a method is , a surface material is laminated on one side of the foam.

The effects obtained by the production method of the present invention can be summarized as follows.

(1) The foamed curable resin composition supplied on the lower belt conveyor 7 or the flexible surface material layered thereon is covered with a flexible surface material layered on the upper belt conveyor 2 or its surface before the start of foaming. Since the flexible surface material 20 is brought into contact with the resin composition, irregularities on the surface of the resin composition can be easily smoothed out. Moreover, since the foaming layer is moved while maintaining contact, and the thickness of the foaming layer is gradually increased, foaming is carried out.
The resulting foam has smooth upper and lower surfaces, uniform thickness, and uniform density. Also,
When a flexible surface material is used, there is no risk of wrinkles occurring in the surface material, there is no risk of voids or gaps forming inside the surface material, and the adhesive strength between the foam and the surface material is strong. A foam with excellent strength can be obtained.

(:1) A pellet conveyor or a flexible surface material is brought into contact with the resin composition before foaming starts, and foaming is carried out by gradually increasing the thickness of the foam layer while maintaining that contact using foaming pressure. The resulting foam has little directionality in cell shape and, in turn, has little directionality in foam quality (for example, compressive strength, bending strength, linear expansion coefficient, etc.).

(li+) Since a belt conveyor or a flexible surface material is brought into contact with the resin composition before foaming starts, a skin layer is formed not only on the lower surface but also on the upper surface of the obtained foam. Therefore, the resulting foam has stable thermal conductivity over a long period of time, excellent rigidity and strength, and improved surface friability.

Next, the present invention will be explained in further detail by giving Examples and Comparative Examples.

Example/ The manufacturing apparatus shown in FIGS. 1 and 2 was used. The upper and lower belt conveyors are made of stainless steel coated with Teflon, the width of both is 300 mm, and the length of the lower belt conveyor is 1 d 23 m.
The upper conveyor was 2'1 m long. In addition, both the upper and lower belt conveyors are heated by 1.0 CK with an appropriate heating device, and a length of 10
A heating open was set up over mK and heated to goc.

The foam-curable liquid resol type phenolic resin composition used had the following composition ratio.

Silicone oil (foam stabilizer) 21 Freon R-/33 (DuPont product name) (foaming agent) /≠ I 30% sulfuric acid (curing agent) 3 parts by weight Lower belt conveyor and upper belt conveyor /r
While rotating at a speed of n/min, the above foamable phenolic resin composition was continuously supplied onto the lower belt conveyor from the supply port g. The number of reciprocating movements of the supply opening was 20 times/min, and the rate of the supply of the resin composition was 001/min. The nip roll /3 is installed at a distance of 0.95 m from the supply port, and the presser roll /I''' is installed at a distance of 0.95 m from the supply port.
It was located at a distance of 7m. The presser foot pressure of each roll is
Nip roll/3 is about O0/kf/crn! , presser roll/l is approximately 0.2 kf/cm', same o-le/17'
is approximately Q, 3 kp/cm", and the same roll/l" is approximately 0
．． 1 force/C1n", same o-le/11t"'K approximately 01
The weight was controlled to be 6 kg/cm.

The presser roll/l'' has a foam layer with a thickness of 3 Q m.
A stopper was provided to stop the rise when it reached m.

Using the above conditions, a phenolic resin foam with a width of soommm and a thickness of 3Qmm could be produced at a speed of 7m7 minutes. The various performances of the obtained foam were as shown in Table 7.

Comparative Example/ By changing the apparatus shown in FIGS. 1 and 2, that is, by not providing any presser rolls /l to c, the nip roll /3 was moved from the supply port g to 2. At the location Qm, the thickness is 3Qmm
Using a device installed so that the foamed foam comes into contact with the upper belt conveyor 2, the upper belt conveyor 2 is transferred to the foam that has reached a thickness of 39 mm just before foaming is completed, according to the conventional method. The rest is in Example/
In the same manner as above, a phenolic resin foam having a width of 300 mm and a thickness of 3 Q mm was produced at a speed of 7 m7 minutes.

The various properties of the obtained foam were as shown in Table 1.

Example 2 As shown in FIG. 3, kraft paper with a basis weight of 100 f/m'' and 2θ are stacked on the surfaces of the lower belt conveyor/and the upper belt conveyor 2, respectively, and the t-hill' is In the same manner as above, a phenolic resin foam having a width of 00 mm and a thickness of 39 mm and having kraft paper laminated on both sides was continuously produced at a speed of im 1 minute.

The various properties of the obtained foam were as shown in Table 1.

Comparative Example: A layer of kraft paper with a basis weight of 00 f//m was placed on the surfaces of the lower belt conveyor A and the upper belt conveyor B, respectively, and kraft paper was pasted on both sides in the same manner as in Comparative Example. Width J' 00 mm, thickness 3Qm
m of phenolic resin foam were produced continuously at a speed of 7 m 7 min.

The various performances of the obtained foam were as shown in Table 7.

Table 7 Table/notes: */...ASTM-2...B5-3927 Hata 3...JIS A-/1112, unit Kcal/
M fist hr-tl?

[Brief explanation of the drawing]

FIG. 7 is a partially cutaway vertical side view of the apparatus in which the present invention is being implemented without using a surface material, FIG. 2 is a partially enlarged vertical side view of FIG. 1, and FIG. 1 is a partially enlarged longitudinal sectional side view of an apparatus implementing the present invention; FIG. Each symbol in the figure is as follows. /...Lower belt conveyor λ...Upper belt conveyor 3...Foaming curable phenolic resin composition preparation tank g...Same resin composition supply port...Same resin composition 10...Same Foaming start point of the resin composition // Foam of the same resin composition / 3 - Nip roll / μ ~ / l ... Presser roll group / za ... Phenol resin foam / 20 ・...Flexible surface material patent applicant Sansin Yuka Co., Ltd.

Claims (1)

[Claims] /) Two endless belt conveyors provided in upper and lower stages are continuously rotated at the same speed in mutually opposite directions, and a foamed curable liquid resol mold is placed on the lower belt conveyor. A phenolic resin composition is continuously supplied, and an upper belt conveyor is brought into contact with the supplied resin composition before foaming starts, and while the conveyor belt is moved while maintaining the contact, the resin composition is heated by foaming pressure. The thickness of the foam layer is gradually increased, and after the foam layer of the resin composition reaches a predetermined thickness, the resin composition is foamed while moving while maintaining the contact and thickness. and a method for continuously producing a phenolic resin foam, characterized by completing curing. 2) The two endless belt conveyors provided in the upper and lower stages are continuously rotated at the same speed in mutually opposite directions, and the lower belt conveyor is rotated at least to the lower belt. A flexible surface material is continuously layered on one surface, and a foamed curable liquid resol type phenolic resin composition is continuously supplied onto the lower belt conveyor or onto the flexible surface material layered thereon. Before foaming starts, the resin composition is brought into contact with the upper belt conveyor or a flexible surface material layered thereon, and while the contact is maintained, the thickness of the foam layer of the resin composition is determined by foaming pressure. is gradually increased, and then, after the thickness of the foamed layer of the resin composition reaches a predetermined thickness, the foaming and curing of the resin composition is completed while moving the resin composition while maintaining the contact and thickness. A method for continuously producing a phenolic resin foam, characterized by: