DK169351B1 - Process for producing phenol resin foamed materials using pressure - Google Patents

Description

in DK 169351 B1

The use of phenolic resins for solid casts, solid profile moldings and coating foils is well known in the coating and resin industry. Furthermore, free foamed foams made from thermosetting synthetic phenolic resins are known. Although the use of phenolic resin foams may appear attractive for potential use for thermal insulation purposes, such use has been severely limited by the generally poorer insulation properties of known phenolic resin foams in comparison with e.g. polyurethane foams.

The heat insulating ability of a foamed material can generally be assessed by the heat conductivity or heat conductivity. The thermal conductivity or thermal conductivity of a particular insulating material is measured according to ASTM Method 15 C-518 Revised and is dimensionally expressed as

W

20 —-—,

m · K

25 which unit is used throughout the following, where the heat conduction numbers are indicated. The lower the thermal conductivity, the better the insulating quality of the insulating material. Furthermore, the longer the material, such as a foam insulation, can maintain a low thermal conductivity, the better the insulating efficiency of the material over time.

Commonly known phenolic resin foams made from mixtures of thermosetting synthetic phenol - formaldehyde resins, acidic catalysts, surfactants and propellants suffer from initial heat conduction numbers, 35 which are generally unacceptable, and their lack of ability to maintain a low heat content. an acceptable period of time.

Although the specific reasons for both the generally poor initial heat conduction and the increase in the heat conduction rate are largely unknown over time, it is believed that they are at least partially due to such factors as the percentage of closed cells in phenolic resin. the pixel foam and the ability of the cell walls to inhibit the outward diffusion from the cells of trapped gases which have been used as propellants, and the inward diffusion of components into air into the cells.

The present invention relates to a process for the preparation of phenolic resin foams from a foamable phenolic resole resin material containing 40-90 wt.% Resole resin, 1-20 wt.% Of a propellant, 0.1-10 wt.% Of a surfactant, 2-40 wt.% water and 2-35 wt.% of a catalyst acid, and the process of the invention is characterized in that the foamable phenolic resole resin material is fed into a practically closed volume wherein the material is allowed to foam under initial atmospheric pressure until the foam virtually fills in said volume, whereby within the substantially closed volume a pressure exceeding 35 kPa is obtained on the outer surface of the foam.

This pressure exceeding 35 kPa is measured on the surface of the material which forms the outer surface of the foam, but it is assumed that this pressure is practically uniformly distributed throughout the volume of the material.

A process for the preparation of phenolic resin foam sheets is also described in Schaumkunststoffe, Entwicklungen und Anvendungen, Carl Hauser Verlag, Miinchen-Wien (1976), pages 407-410. However, this prior art aims at providing a continuous manufacturing method, and there is no foaming in a practically closed space, as it is expressly stated that the upper limiting band can rise by itself if the foam pressure exceeds 30. kPa. Furthermore, it appears that the characteristic of the finished foam material which is of interest is the lack of flammability, whereas no mention is made of the thermal conductivity which is essential for foam fabric manufactured. by the method of the invention.

Namely, it has been found that the process of the invention is valuable for the production of heat insulation material of phenolic resin foam for widely varying applications in housing and industry. The process is particularly advantageous for the production of phenolic resin foam fabrics with excellent insulating properties from foamable materials based on resole resins made from relatively inexpensive phenol and formaldehyde, preferably as paraformaldehyde. Phenolic resin foams produced by the process of the invention exhibit not only a good heat conduction number to begin with, but also a good heat conduction number retention, unlike known phenolic resin foams. Therefore, the process of the invention achieves a long-sought but previously not achieved goal, namely to produce a phenolic resin foam having both a good heat conduction number to begin with and a good retention of heat conduction numbers from phenolic resole resins such as simple phenol / formaldehyde resole resins, and The process therefore represents an important advance in the field of phenolic resin foam.

In the drawing, the same numbers refer to the same parts in the individual figures, of which fig. Figures 1A and 1B in partial cross-sectional diagram form show practically closed molds; Figure 2 is a diagrammatic side view of a foam forming machine; 3 is a partial sectional view taken along line III-III of FIG. 2, 30 FIG. 4 is a diagrammatic cross-sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a diagrammatic cross-sectional view taken along the line V-V in FIG. Third

In one embodiment of the invention, the foamable phenolic resole resin material is fed into a rigid, practically closed mold 1, e.g. as shown in FIG. 1A and DK 169351 B1 4 IB, and are initially allowed to expand under virtually atmospheric pressure. The mold 1 contains apertures 2, e.g. the narrow gaps where the sides of the mold are clamped together. As the foamable material expands to fill the mold, the openings become sealed by the material itself as it displaces the air in the mold as it foams. The phenolic foamable material has such a composition that, when the foam is expanded to fill and seal the mold, it will create a pressure on the mold walls exceeding 35 kPa. This pressure can e.g. is measured by means of a pressure gauge 3 which is attached to a wall of the mold, the pressure gauge being able to respond to the pressure created in the mold by means of e.g. a flexible membrane 4, as shown in FIG. 1A, or a movable piston 8, as shown in FIG. IB, in contact with the trapped foam. The pressure created by the trapped foam within the mold is above 35 kPa and preferably above 42 kPa overpressure.

In another embodiment of the invention, using a continuous processing technique, a pressurized phenolic resole foam resin foam is produced in a machine of the type illustrated schematically in FIG.

2. The foamable material is applied to a lower abutment material 25, such as a carton containing a thin layer of aluminum, a glass mat, a rigid support such as wood fiberboard, or a vinyl skin, which material is caused to leave a container 26 and move along a table. 29 by means of a lower conveyor belt 12. The foamable material is supplied by means of a distributing means 30 which moves forward and backwards across the direction in which the lower abutment material 25 moves, although any suitable means for even distribution of the material , eg. a multiple mixing head can be used. As the foamable material advances, it begins to foam and comes into contact with an upper abutment material 27, which, by means of rollers 22 and 23, is directed to the area where the foamable material is at a very early stage. expansion stage. As the foamable material initially expands under practically atmospheric pressure, it is introduced into a cure cavity 28 formed by the lower portion of an upper conveyor belt 11, the upper portion of the lower conveyor belt 12, and two solids. rigid side walls, called side frames, not shown in FIG. 2, but shown at 41 and 42 in FIG. 3. The thickness of the foam is determined by the distance between the upper conveyor belt 11 and the lower conveyor belt 12. The upper conveyor belt 11 10 can be moved perpendicular to the lower conveyor belt which cannot be lifted or lowered by any suitable lifting means (not shown). As the upper conveyor belt 11 is lifted or lowered, it moves between the rigid sidewalls 41 and 42, as shown in FIG. 3, the walls adjacent 15 immediately to the sides of the upper conveyor belt 11. The surfaces of the conveyor belts in contact with the upper and lower abutment materials comprise a plurality of printing plates 13 and 14 which are attached to the conveyor belt by rigid fastening means. 21. The pressure plates are generally heated by hot air 20 which is fed into and circulated within the upper and lower conveyor belts by means of air inlets not shown in the drawing.

Along with the upper and lower abutment papers, side papers 43 and 44 are guided as shown in FIG. 3, which papers contain a foam-releasing material, such as a thin film of polyethylene, into the cure cavity by rollers 45 and 46 and such means as guide pieces 47 and 50. Each of the guide pieces is disposed just in front of the cure cavity 28, such that the side papers 43 and 44, before they come into contact with the side walls 41 and 42, overlap the upper and lower abutments, e.g. as illustrated in FIG. 4. When the side papers 43 and 44 come into contact with the side walls 41 and 42, they are flattened as illustrated in FIG. 5th

When the foam is expanded to fill the cure cavity thickness, further expansion is limited by e.g. the pressure plates 13 and 14 as shown in FIG. 2 DK 169351 B1 6 and the side walls 41 and 42 as shown in FIG. 3 so that the foam fabric exerts a pressure on the pressure plates and side walls of a size suitable for the purposes of the invention, namely above 35 kPa and preferably above 42 kPa.

Treatment parameters, such as the amounts of the foamable components, the flow rate of the material from the distributor, the temperature of the air circulating into the conveyor belts, and the conveyor belt velocity can be widely varied in the practice of the invention, such that on the outer surface of the foam in the cure cavity, a pressure is created in accordance with the invention.

After the phenolic resin foam has left the cure cavity, the side papers 43 and 44 are removed by means of e.g. rollers 48 and 49 as shown in FIG. 3. The foam can be cut to the desired lengths depending on the intended use.

Phenolic resin foams prepared using the process of the invention generally have total weights (i.e. including foam skin) ranging from 24 to 80 kg / m 3, and preferably ranging from 32 to 56 kg / m 3, and core weights (i.e., without foam skin) which ranges from 24 to 72 kg / m 3 and preferably ranges from 32 to 48 kg / m 3. The phenolic resin foams are foamed with practically closed cells, usually containing at least 85% closed cells, typically at least 90% closed cells and preferably more than 90% cells, e.g. as measured by an air pycnometer according to ASTM-D 2856-70 (1976).

Phenolic resin foam fabric manufactured by the method of the invention has both a low heat conduction number to begin with and an ability to maintain a low heat conduction number for a long period of time. A "low heat conduction number" is to be understood as meaning a heat conduction number of 35 below 0.031 which is approximately the conduction number of a foam containing air. A "low heat conduction number to begin with" shall be understood as meaning a heat conduction number of less than 0.031 when measured approx. 24 hours after the foam has been produced. Phenolic resin foams prepared by the process of the invention generally have a heat conduction number initially of 0.022 or less, typically 0.020 or less and preferably 0.019 or less. In addition, phenolic resin foams prepared by the process of the invention generally maintain a heat conduction number after 10 days of aging at room temperature 10 of 0.022 or less, typically 0.020 or less and preferably 0.019 or less. As used herein, a phenolic resin foam having "substantial thermal conductivity retention" is to be understood as having a thermal conductivity of 0.022 or less after aging at room temperature for 10 days. It is preferred that the foam retains a heat conduction number of less than 0.031 for extended periods, e.g. after aging at room temperature for 60 days, for 90 days or longer. The longer a foam retains a low thermal conductivity, the better it is as a heat insulating material.

The foamable phenolic resole resin material used in the process of the invention comprises a phenolic resole resin, a propellant, a surfactant, a catalyzing acid and water. However, it is to be understood that the practice of the invention in its broadest aspects is not to be limited by the specific composition of the foamable phenolic resole resin material, provided that the foamable phenolic resole resin material is composed such that the above 30 amounts of its individual components, thereby providing within the substantially closed volume a pressure as discussed above.

The phenolic resole resin may be prepared by generally known methods which involve the reaction of one or more phenolic compounds with one or more aldehydes under alkaline conditions. In general, a phenol compound and aldehyde mole ratio ranging from 1: 1 to 1: 2, preferably from 1: 1.4 to 1: 1.6, is used.

Although phenol itself is preferably used as the phenolic component of the resole resin, it will be appreciated that the process 5 of the invention can also be used with phenolic resole materials derived from other phenolic compounds. Eg. other compounds having a phenolic hydroxyl group and from 2 to 3 unsubstituted ring carbon atoms in ortho and para position to the phenolic hydroxyl group are suitable.

Such compounds include both mononuclear phenol compounds and polynuclear phenol compounds, although mononuclear phenol compounds are preferred and phenol itself is particularly preferred. Polynuclear phenolic compounds are compounds with more than one benzene nucleus to which a phenolic hydroxyl group is attached.

Examples of suitable mononuclear phenols include e.g. phenol, resorcinol, catechol, hydroguinone, ortho-, meta- and para-cresols, 2,3-, 2,5-, 3,4- and 3,5-xylenols, 3-ethylphenol and 3,5-diethylphenol. Examples of suitable dinuclear compounds include 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) -butane and 2,2-bis- (4-hydroxyphenyl) propane. 3-methyl-phenyl) propane. It is to be understood that the above phenolic reactants can be used alone or in combination for the preparation of the phenolic resole resins used in the process of the invention.

Examples of suitable aldehydes for the preparation of the phenolic resole resin include formaldehyde, acetaldehyde, furfural, glyoxal and benzaldehyde. In addition, formaldehyde can be used as free formaldehyde, e.g. in the form of an aqueous solution such as formalin, or in the form of its low molecular weight polymer such as paraformaldehyde. Other substances which can provide free formaldehyde under the condensation reaction conditions during resole formation may also be used. Of the above aldehydes, formaldehyde is preferred, especially as paraformaldehyde.

It is particularly surprising that phenolic resin foams DK 169351 B1 9 with practically closed cells and with a good heat conduction number initially and a good retention of the heat conduction number can be prepared by the process of the invention from substantially resole resins. 5 prepared from phenol itself and formaldehyde. Eg. Foams prepared by the process of the invention using phenol resin made from phenol itself and paraformaldehyde exhibit better thermal insulation properties than e.g. well-known foams which have been allowed to foam freely, essentially from phenol / paraformaldehyde resole resins.

The viscosity of the phenolic resole resins used according to the invention generally ranges from 500 to 50,000 mPa * s at 25 ° C. Preferably, the viscosity 15 ranges from 4,000 to 10,000 mPa * s at 25 ° C.

The amount of phenolic resole resin present in the foamable materials used in the invention for the preparation of practically closed cells phenolic resin foams can vary widely, provided that the amount is sufficient to produce such a foam. i.e. the amount of the phenolic resole resin present in the foamable material is from 40% to 90% by weight of the material. Typically, the amount of phenolic resole resin ranges from 50 to 80% by weight of the material. An amount of between 55 and 65% by weight of the foamable material is preferred.

The propellant is generally a halogen-containing propellant, preferably a fluorine-containing propellant. Examples of suitable fluorine-containing propellants include monochlorodifluoromethane, dichlorodifluoromethane, 1,2-dichloro-1, 1,2,2-tetrafluoro-ethane, 1,1,1-trichloro-2,2,2-trifluoroethane, 1, 2-difluoroethane, trichloromonofluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, 1,1,2,2-tetrachloro-1,2,3-difluoroethane and 1,1,1,2-tetrachloro-2,2-difluoroethane.

35 DK 169351 B1 10

The propellant may be a single compound or it may be a mixture of such compounds. Usually, the fluorine-containing propellants used have boiling points at atmospheric pressure in the range of -5 ° C to 55 ° C. A boiling point at 5 atmospheric pressures of between 20 ° C and 50 ° C is typical. The preferred propellant is a mixture of trichloromonofluoromethane and 1,1,2-trichloro-1,2,2-trifluoroethane. In particular, it is preferred that the weight ratio of the trichloromonofluoromethane to the 1,1,2-trichloro-1,2,2-trifluoroethane in the mixture be approx. 1: 1.

The propellant is present in the foamable material in an amount which will produce phenolic resin foam with practically closed cells and with a low heat conduction number to begin with. The amount of propellant may vary within wide limits, namely from 1% to 20% by weight of the foamable material. An amount of propellant of from 5 to 15% by weight of the foamable material is typical. An amount of between 8 and 13% by weight is preferred.

The surfactant has such properties that it is possible to effectively emulsify the contents of the foamable material. To produce a good foam, the surfactant should reduce the surface tension and stabilize the foam cells during expansion. Usually, a surfactant silicone agent is used, although any surfactant having the above-described necessary properties can be used. Specific examples of suitable surfactants include the surfactant silicone agents nL-7003n, "L-5340" and L-5310 ", all from Union Carbide Corporation, as well as" SF-loee "from General Electric Company.

The surfactant used in the foamable material may be a single surfactant or a mixture of surfactants. In the process of the present invention, the surfactant is used in an amount sufficient to produce an emulsion, i.e. in an amount from 0.1 to DK 169351 B1 11 10% by weight of the foamable resole resin material. Typically, the amount ranges from 1 to 6% of the material. An amount of surfactant of from 2 to 4% by weight of the material is preferred.

Usually, some water is desirable in the foamable material to adjust the viscosity of the material to that which is favorable for the production of foams.

Although the water present in the foamable material probably evaporates and contributes to the creation of the pressure in the practically closed volume, water is not considered to be particularly advantageous as a propellant. Therefore, as used herein, the term "propellant" is to be understood as not including water. The water can be added in admixture with some or all of the other components of the foamable material. The water can be added directly as such or in combination with any of the components described above. Usually some water is introduced into the material in admixture with the phenolic resole resin and some is introduced in admixture with the catalyst acid.

The water present in the foamable material is present in an amount which adjusts the viscosity, ie. 2 to 40% by weight of the foamable material. Typically, the amount of water ranges from 5 to 30% by weight of the material. An amount of water ranging from 10 to 25% by weight of the foamable material is preferred.

The catalytic acid component serves to catalyze the reaction of the resole resin to form a thermoset polymer during foaming. The catalyst acid may be an inorganic or organic acid commonly known for acid catalysis of phenolic foaming. Examples of suitable catalyst acids are hydrochloric acid, sulfuric acid, fluoroboric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, mixtures of acidic catalysts based on boric acid or its anhydride with organic hydroxy acids with hydroxyl group or a carbon atom which is at most one carbon atom removed from the carboxyl group. pen, such as oxalic acid, as described in U.S. Pat.

DK 169351 B1 12 3,298,973, or other acid catalysts known in the art for phenolic foaming. Examples of other suitable catalyst acids are organic sulfonic acids such as benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid and butanesulfonic acid, as well as resin sulfonic acids such as diphenol / sulfuric acid / formaldehyde reaction products described in GB Patent No. 1,283,113.

Preferred catalyst acids are those disclosed in U.S. Patent Application No. 138,476 on phenolic foam materials. These catalyst acids comprise an aromatic sulfonic acid from the group consisting of phenolic sulfonic acid, cresol sulfonic acid, xylene sulfonic acid and mixtures thereof, and an alkanesulfonic acid of the group consisting of methanesulfonic acid, ethanesulfonic acid and mixtures thereof. The catalyst acid used in the process of the present invention preferably consists essentially of the aromatic sulfonic acid and the alkanesulfonic acid, in particular phenolic sulfonic acid and methanesulfonic acid.

Generally, when present, the amount of aromatic sulfonic acid ranges from 30 to 95% by weight of the catalyst acid, with an amount ranging from 50 to 80% of the catalyst acid being preferred. Generally, when present, the amount of alkanesulfonic acid ranges from 5 to 70% by weight of the catalyst acid, with an amount ranging from 20 to 50% of the catalyst acid being preferred.

A single aromatic sulfonic acid may be used as the aromatic sulfonic acid component of the catalyst acid, or a mixture of such acids may be used. When a mixture is used, the individual aromatic sulfonic acids may be from the same class, e.g. all may be phenolic sulfonic acids, cresol sulfonic acids or xylenol sulfonic acids, or they may be from different classes. The preferred aromatic sulfonic acid is phenolic sulfonic acid. Particularly preferred is commercial phenolic sulfonic acid, which is primarily a mixture of o-phenolic sulfonic acid 35 and p-phenolic sulfonic acid, with some m-phenolic sulfonic acid being present as well.

DK 169351 B1 13

The alkanesulfonic acid component of the catalyst acid may be methanesulfonic acid, ethanesulfonic acid or a mixture of these two acids.

The amount of catalyst acid present in the foamable material can vary within wide limits, namely from 2 to 35% by weight of the material. Typically, the amount of catalyst acid ranges from 5 to 30% by weight of the foamable material. An amount of catalyst acid ranging from 6 to 20% by weight of the material is preferred.

When, as preferred, the catalyst acid is essentially composed of the aromatic sulfonic acid and the alkane sulfonic acid, the aromatic sulfonic acid is usually present in an amount of between 0.6 and 33.25% by weight of the foamable material, and the alkanesulfonic acid is usually present in an amount of between 0.1 and 24.5% by weight of the foamable material. Typically, the amount of aromatic sulfonic acid is between 1.5 and 28.5% by weight of the foamable material, and the amount of alkanesulfonic acid is between 0.25 and 21% by weight of the material. Preferably, the amount of 20 aromatic sulfonic acid is between 3 and 16% by weight of the foamable material and the amount of alkanesulfonic acid is between 1.2 and 10% by weight of the material.

The above-described proportions and amounts of catalyst acid and its constituents are calculated on the basis of anhydrous acids.

Other known materials can be added in their usual quantities for their usual purposes as long as they do not seriously interfere with good foaming practices.

Any practically closed volume may be used in the method of the invention. The walls defining this volume may be of any size, shape and material, provided that they are able to withstand the pressure created within this volume in the practice of the invention. Pressure exceeding 35 kPa is achieved on the walls 35 that delimit this volume. Preferably, a pressure DK 169351 B1 14 above 42 kPa is obtained. Unless otherwise indicated, pressure values mentioned in the present description are to be understood as significant overpressures, ie. pressure in addition to the ambient pressure of approx. 100 kPa. Some specific examples of practically closed volumes for practicing the invention include a practically closed mold or cure cavity in a continuous foam forming machine.

The maximum pressure created by the foam forming material in the practically closed volume will vary, e.g. depending on the density of the phenolic resin foam fabric produced. Generally, a maximum pressure is obtained which varies up to approx. 211 kPa, typically up to approx.

105 kPa overpressure.

The hardening of the foamable material is exothermic, and the temperature during the hardening varies. Usually, curing is carried out at a temperature of between 4 ° C and 122 ° C. Curing temperatures of from 15 ° C to 99 ° C are preferred.

The following examples illustrate the invention.

20 Parts and percentages are by weight unless otherwise specified.

Example 1 (a) Preparation of a phenol-formaldehyde resole resin.

In a reactor equipped with a thermometer, stirrer, heater and reflux, 1500 g of an aqueous 90% phenol solution (14.4 moles of phenol) and 1690 g of an aqueous 37% formaldehyde solution (20.8) are charged. moles of formaldehyde). The phenol-formaldehyde mixture is heated to 40 ° C and 36 g of an aqueous 12.5% sodium hydroxide solution is added. Then, the mixture is slowly heated for 86 minutes to a temperature of 98 ° C, then an additional 36 g of aqueous 12.5% sodium hydroxide solution is added. The temperature is kept at 98 ° C in

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15 minutes, then 36 g of the 12.5% sodium hydroxide solution is added for the third time. The temperature is kept within a deviation of approx. 1 g for another 15 minutes, then for the fourth time 36 g of 12.5% sodium 5 hydroxide solution is added. The temperature of the mixture is kept at 99 ° C for 59 minutes, after which the mixture is cooled to 80 ° C over 5 minutes. The mixture is kept at 80 ° C for 1 hour and then cooled to 30 ° C over 18 minutes, after which 37.8 ml of an aqueous 45% * formic acid solution is added. The mixture is then stirred for 17 minutes at 30 ° C and a pH value reading of 5.4. The resulting phenol-formaldehyde resole resin is then evaporated under nitrogen at reduced pressure. The resin has a Brookfield viscosity of 20 ° C at 4300 mPa · s. The resin has a residual formaldehyde content of 0.7%, a hydroxyl number of 659, a water content of 16.3% and a dry matter content of 81.01%.

(b) Preparation of a foam.

A foamable material is prepared by admixing 20 55 parts of the phenol-formaldehyde resole immediately described above, 1.4 parts of surfactant silicone "L 5310", 4.6 parts of 1,2, 2-trichloro-1,2, 2-trifluoroethane, 2.3 parts of trichloromonofluoromethane, 3.2 parts of aqueous 50% sulfuric acid and 3.2 parts of ethylene glycol. 160 g of the foamable material is stirred for 20 seconds and poured into a 30 x 30 x 2.5 cm mold, which has already been heated to 37.8 ° C. The mold is closed in a tension, leaving only narrow openings at the edges of the mold. The mold is placed in a curing oven at 54.4 ° C for 24 hours during which the foamable material expands to seal the openings and create a pressure greater than 35 kP on the mold walls.

The resulting foam has a density of 65.4 kg / m, an initial heat conductivity of 0.0183, a heat conductivity after aging for 12 days of 0.0214, and a heat conductivity after 31 days of 0.0319.

DK 169351 B1 16 o

Example 2 (a) Preparation of two phenol-formaldehyde resole resins.

(i) Part (a) of Example 1 is repeated until the addition of the first 36 g of aqueous 12.5% sodium hydroxide. Then the mixture is slowly heated for 1 hour and 35 minutes to a temperature of 99 ° C, after which an additional 36 g of aqueous 12.5% sodium hydroxide is added. The temperature is kept at 99 ° C for 15 minutes and then 36 g of 12.5% sodium hydroxide is added for the third time. The temperature is controlled within a deviation of approx. 1 g for another 15 minutes, then for the fourth time 36 g of 12.5% sodium hydroxide solution is added. The mixture is cooled over 30 minutes to 92 ° C, keeping the temperature for an additional 30 minutes. Then the mixture is cooled to 80 ° C over 2 minutes and kept at 80 ° C for 15 hours. The mixture is then cooled to 30 ° C over 18 minutes and a total of 34 ml of aqueous 48.5% formic acid solution is added. The phenol-formaldehyde resole resin is then evaporated under nitrogen at reduced pressure. The resin has a viscosity of 6000 mPa · s at 20 ° C, a residual formaldehyde content of 0.65%, a hydroxyl number of 673, a water content of 16.3% and a solids content of 76.0%.

(ii) In a reactor equipped with a thermometer, a stirrer, a heating means and a refluxer, 1500 g of a 90% aqueous phenolic solution and 24 g of barium hydroxide are charged. This mixture is heated to 40 ° C and 330 g of 91% paraformaldehyde is added. The mixture is heated for 25 minutes to a temperature of 105 ° C and then cooled to 85 ° C over 90 minutes. Then an additional 330 g of 91% paraformaldehyde is added and the temperature is maintained at 85 ° C for 1 hour. Then, the mixture is cooled to 30 ° C over 15 minutes and 6 g of aqueous 48.5% * formic acid are added. The phenol-formaldehyde resin resin is then evaporated under nitrogen at reduced pressure. The resin has a viscosity of 4200 mPa.s at 20 ° C, a residual formaldehyde content of 3.2%, a hydroxyl number of 807, a water content of 3.9% and a solids content of 72.74%.

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(B) Preparation of a foam.

A foamable material is prepared by admixing 105 parts of the phenol-formaldehyde resin described above in part (a) (i), 45 parts of the phenol-formaldehyde described immediately in part (a) (ii) resin, 3.6 parts surfactant silicone "L-5310", 15.0 parts 1,1,2 - trichloro-1,2,2-trifluoroethane, 9.6 parts ethylene glycol and 14.4 aqueous 50% sulfuric acid. The mixture is stirred for 15 seconds and poured into a 30 x 30 x 2.5 cm aluminum mold at 10 room temperature. The mold is closed in tension, leaving only narrow openings at the edges of the mold. The foamable material is allowed to expand at room temperature for 1 minute to seal the openings in the mold. Then, the mold is placed in a curing oven at 76.7 ° C for 16 hours and 15 minutes-15, during which a pressure of over approx.

35 kPa.

The cured foam contains 85% closed cells as measured using an air pycnometer according to ASTM-3-D2856-70 and has a density of approx. 56 kg / m. The foam 20 has an initial heat conduction number of 0.0174.

The heat conductivity of the foam when aging is shown in Table I below.

Table I

25 Aging period Heat conduction number 12 days 0.067 13 days 0.0173 33 days 0.0193 61 days 0.0284 30

A comparison of data from Example 2 shows that the heat conduction number decreases for a short time after the initial measurement. Although the factor (s) responsible for this decline is not fully understood, it is believed that the cells after the formation of the foam alone are not alone 169161 B1

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18 contains halogen-containing gas but also water in the form of steam, liquid or both steam and liquid. Since the water molecules are smaller than the molecules of the halogen-containing gases, the water molecules can diffuse outward at a higher rate. Since water even has a higher thermal conductivity than the halogen-containing gases, the result is a decrease in the observed thermal conductivity of the foam initially. As the effect of the diffusion of water molecules decreases, the effect of the slower outward diffusion of the halogen-containing gases manifests itself with a gradual increase in the heat conduction rate upon further aging. Whether or not the temporary decrease in heat conduction is observed depends on the observation times in relation to the duration of the effect.

Example 3 (a) Preparation of two phenol-formaldehyde resins (i) Part (a) of Example 1 is repeated until the addition of the first 36 g of aqueous 12.5% sodium hydroxide. The mixture is then slowly heated over 90 minutes to a temperature of 99 ° C, after which an additional 36 g of 12.5% sodium hydroxide is added. The temperature is kept between 99 ° C and 98 ° C for 15 minutes, then for the third time 36 g of 12.5% sodium hydroxide is added. The temperature is regulated within a deviation of approx. At a temperature of about 2 ° C for a further 15 minutes, after which 25 g of the 12.5% sodium hydroxide solution are added 36 g. The temperature of the mixture is then slowly lowered over 1 hour to 92 ° C and to 80 ° C and maintained at ca. 80 ° C for an additional 1 hour. Next, the mixture is cooled to 30 ° C and 34 ml of aqueous 48.5% formic acid is added so that the mixture has a pH of 6.54. The phenol-formaldehyde resole resin is evaporated under nitrogen at reduced pressure. The resin has a viscosity of 6800 mPa · s at 20 ° C, a residual formaldehyde content of 0.62%, a hydroxyl number of 661, a water content of 11% and a dry matter content of 82.4%.

35 DK 169351 B1

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(Ii) Part (a) (ii) of Example 2 is repeated until the addition of 330 g of 91% paraformaldehyde at 40 ° C. The mixture is heated for 30 minutes to a temperature of 110 ° C and then allowed to cool to 85 ° C over the next 5 minutes.

5 The temperature of the mixture is kept at approx. 85 ° C for 1.5 hours, then an additional 330 g of 91% paraformaldehyde is added. The temperature is kept at approx. 85 ° C for 1 hour, then cool to 30 ° C. The phenol-formaldehyde resole resin is then evaporated under nitrogen at reduced pressure. The resin has a viscosity of 1800 mPa.s at 20 ° C, a residual formaldehyde content of 3.95%, a water content of 3.6% and a solids content of 61.8%.

(b) Preparation of a Foam 15 A foamable material is prepared by mixing 105 parts of the phenol-formaldehyde resin described immediately above in part (a) (i), 45 parts of the immediately above part (a) (ii) described pheno1-formaldehyde resin, 3.6 parts surfactant silicone "L-5310", 1.5 parts 20 l, l, 2-trichloro-1, 2,2-trifluoroethane, 9.6 parts ethylene glycol and 14.4 parts aqueous 50% sulfuric acid. The foamable material is stirred for 15 seconds and poured into a 30 x 30 x 2.5 cm aluminum mold which has been preheated to 71.1 ° C. The mold is closed in a tension, leaving only 25 openings at the edges of the mold. The mold is placed in a curing oven at 71.1 ° C for 17 hours, whereby the foamable material expands to seal the openings and create pressure on the mold walls in accordance with the invention.

3

The resulting foam has a density of 61 kg / m

AA

and an initial heat conduction number of 0.078. The thermal conductivity of the foam during aging is shown in Table II below.

35 0 DK 169351 B1 20

Table II

Aging period Heat conductivity 12 days 0.0169 31 days 0.0185 5 62 days 0.0208 160 days 0.0274

Example IV

(a) Preparation of two phenol-formaldehyde resole resins (i) In a reactor equipped with a thermometer, stirrer, heater and reflux 450 g of solid phenol, 220 g of aqueous 91% paraformaldehyde, 19 g water and 6 g aqueous 50% sodium hydroxide. The mixture is heated to 100 ° C. Then, the mixture exothermically reaches 125 ° C over 3 minutes after reaching 100 ° C and it is cooled to 100 ° C. Thereafter, the temperature of the mixture drops to 95 ° C over 57 minutes, after which it is cooled to 80 ° C over a further 35 minutes. At 80 ° C, 7.0 g of aqueous 45.5% of 20 formic acid is added to the mixture, which is then allowed to cool to room temperature. The resulting phenol-formaldehyde resole resin has a viscosity of 5,200 mPa * s, a residual formaldehyde content of 0.75%, a water content of 12.7%, a hydroxyl number of 685 and a solids content of 81.3%.

(Ii) In a reactor equipped with equipment as described above, a mixture of 1690 g of Aqueous 37% formaldehyde and 24 g of barium hydroxide is charged. The mixture is heated to 40 ° C and then 375 g of aqueous 90% phenol is added. This mixture is heated to a temperature of 99 ° C for 105 minutes, after which 30 additional 375 g of 90% phenolic solution are added. The mixture is cooled for 30 minutes to 85 ° C, then an additional 375 g of 90% phenol solution is added. The temperature is kept at approx. 85 ° C for 30 minutes, then add the last 375 g of 90% phenolic solution. The mixture is kept between 85 ° C and 80 ° C for 90 minutes and then cooled to 30 ° C, then 6 ml water

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21 DK 169351 B1 you 48.5% formic acid is added. The resulting phenol-form-aldehyde resin resin, after evaporation under nitrogen at reduced pressure, has a viscosity of 400 mPa-s, a residual formaldehyde content of 3.4%, a water content of 3.4%, a hydroxyl number of 747 and a dry matter content of 43.7%.

(b) Preparation of a foam.

A foamable material is prepared by mixing 120 parts of the 10 phenol-formaldehyde resin described above in part (a) (i), 30 parts of the phenol-formaldehyde-resin resin described above in part (a) (ii) pixel, 3.6 parts surfactant silicone "L-5310", 15 parts l, l, 2-trichloro-1, 2,2-trifluoroethane, 9.6 parts ethylene glycol and 14.3 parts aqueous 50% sulfuric acid . The mixture is stirred 15 for 12 seconds and poured into a 30 x 30 x 2.5 cm aluminum mold which has already been heated to 70 ° C. The mold is closed in tension as in Example 1 (b) and placed in a curing oven at 70 ° C for 16 hours, whereby the foamable material expands to seal openings and create pressure on the walls of the mold according to the invention.

3

The cured foam has a density of approx. 59 kg / m. The foam has an initial heat conduction number of 0.0181. The heat conductivity of the foam when aging is shown in Table III below.

25

Table III

Aging period Heat conductivity 11 days 0.0173 64 days 0.0180 30 9 0 days 0.0187 120 days 0.0185 156 days 0.0191 305 days 0.0202 341 days 0.0206 35 363 days 0.0205 500 days 0.0222

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DK 169351 B1 22

Example 5 (a) Preparation of a phenol-formaldehyde resin.

A catalyst material is prepared by mixing 6 g of potassium hydroxide beads with a purity of approx. 85% and 3.6 g of water.

A starting material is prepared by mixing 1044 g of aqueous 90% phenol and 9.6 g of the above catalyst material.

In a reactor equipped with a thermometer, a stirrer, a heating means and a reflux condenser 1044 g of 90% phenol and 990 g of 91% paraformaldehyde are charged and 100 ml of the starting material is added. Then additions of the starting material are made according to the following scheme: 15 Time interval since the reaction mixture addition, the starting material of the mixture, minutes_ temperature, ° C _ milliliters_ 10 70 100 10 70 100 20 10 70 100 10 80 100 10 80 100 10 80 100 10 80 100 25 10 80 100 10 80 100 One minute later, the temperature is 90 ° C. The reaction mixture is then maintained at 90 ° C for 3/4 hours. At the end of this period, cooling begins. 25 minutes later, the temperature is 78 ° C and cooling is interrupted. The reaction mixture is maintained at 78-79 ° C for 2 hours and 5 minutes. An addition of 4.5 g aqueous 90% aqueous formic acid is added and the reaction mixture is cooled and stored in a refrigerator. The resulting phenol-formaldehyde resole resin has a viscosity of 6800 m @ 25 at 25 ° C.

(b) Preparation of a foam.

A foamable material is prepared by admixing 5 of 74.6 parts of the phenol formaldehyde resin immediately described above, 3.4 parts surfactant silicone "L-7003", 5 parts 1,1,2-trichloro-1, 2,2-trifluoroethane, 5 parts trichloromonofluoromethane, 9 parts 65% aqueous phenolic sulfonic acid and 3 parts aqueous 70% methanesulfonic acid.

The mixture is poured into a pre-heated 27 x 35 x 4 cm aluminum mold coated with mold release agent. Then, the mold is closed in tension as in Example 1 (b) and placed in an oven at 71.1 ° C for 15 minutes, whereby the foamable material expands to seal openings and create 15 pressures on the walls of the mold in accordance with the invention.

3

The cured foam has a density of approx. 56 kg / m and an initial heat conduction number of 0.0179. The heat conductivity of the foam when aging is shown in Table IV below.

Table IV

Aging period Heat conduction number 10 days ©, 0200 100 days 0.0208 183 days 0.0212 25

Example 6 (a) Preparation of a phenol-formaldehyde resole resin.

A catalyst material is prepared by mixing 403.2 g of potassium hydroxide with a purity of approx. 85% and 241.9 g of water.

In a reactor equipped with a thermometer, a stirrer, a heating means, a cooling means and a total refluxer, 67.95 kg of aqueous 90% phenol and 64.5 kg of 91% paraform aldehyde chips are charged. In the reactor, after 6.8 kg of 90% phenol and 40 ml of the above catalyst material are charged. They filled

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B materials are heated to 66.1 ° C and an additional 6.8 kg of aqueous 90% phenol and 40 ml of the above catalyst material are added. 15 minutes later, when the temperature of the reaction mixture is 68.9 ° C, an additional 6.8 kg of 90% phenol 5 and 40 ml of catalyst are added. The reaction mixture is heated to 73.3 ° C for 15 minutes, and an additional 6.8 kg of 90% phenol and 40 ml of catalyst are added. Then, the reaction mixture is heated to 82.2 ° C over a period of 5 minutes and further addition of phenol and catalyst in the same 10 amounts as above. Four further additions of phenol and catalyst in the same amounts as above are made at 10 minute intervals when the temperatures are 80.0, 82.8, 83.3 and 82.2 ° C, respectively. At the end of a further 10 minute interval, when the temperature is 82.8 ° C, 6.7 kg of 90% phenol and 40 ml of the above catalyst material are added. The reaction mixture is then heated for 10 minutes to a temperature of 87.8 ° C. For the next 3 hours and 55 minutes, the reaction mixture is kept at a temperature between 85.6 ° C and 89.4 ° C and then cooled to a temperature of 80 ° C over the next 1 hour 20 and 50 minutes. to which point 282.3 g of aqueous 90% formic acid is added.

(b) Preparation of six foams.

A foamable material is prepared by admixing the phenol-formaldehyde resole resin immediately described in part (a), 3.4 parts surfactant silicone "L-7003", 6 parts ortho-cresol, 5 parts l, 1.2 -trichloro-1,2,2-trifluoroethane, 5 parts trichloromonofluoromethane, 3 parts aqueous 70% methanesulfonic acid and 9 parts aqueous 65% phenol-sulfonic acid.

The blends are poured into molds coated with mold abrasive. The molds are provided with a manometer as schematically illustrated in FIG. 1A. The molds are closed in tension so that only narrow openings are left at the edges of the mold and placed in a curing oven at 71.1 ° C for 15 minutes. It

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DK 169351 B1 25 foamy material expands to seal the openings and create pressure on the walls of the mold. Manometer readings are made after the molds are placed in the curing oven, and these pressure readings and times are shown in Table V. The total foam weight filler, core weight filler and heat conduction numbers for the cured foam materials are also included in Table V.

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DK 169351 B1 27

Example 7 (a) Preparation of Two Phenol-Formaldehyde Resol Resins (i) A catalyst material is prepared by mixing 5 of 8.46 parts of potassium hydroxide having a purity of approx. 85% and 7.52 parts of deionized water.

A starting material is prepared by mixing 1425 parts of aqueous 90% phenol and 15.98 parts of the above catalyst material.

In a reactor equipped with a thermometer, a stirrer, a heating means, a cooling means and a total reflux, 1425 parts of aqueous 90% phenol and 1352.7 parts of 71% paraformaldehyde chips are filled. The filled materials are heated to 7 9.4 ° C. Over a period of 2 hours and 55 minutes, while the temperature is between 71.1 ° C and 86 # 7 ° C, 1440.98 parts of the above starting material are added. Then, the reaction mixture is heated to 83.9 ° C for 10 minutes and then maintained between 82.8 ° and 86.1 ° C for 7 hours and 15 minutes. Next, the reaction mixture is cooled for 2 hours and 10 minutes 20 to 71 ° C and 5.92 parts of aqueous 90% formic acid is added. The reaction mixture is further cooled for 1 hour to 54.4 ° C and 190 parts of liquid ortho-cresol added.

The product, a phenol-formaldehyde resole resin, has a viscosity of 3000 mPa · s at 25 ° C.

(Ii) Part (i) immediately above is repeated until the reactor is filled with 1425 parts 90% phenol and 1352.7 parts 91% paraformaldehyde chips.

The filled materials are heated to 79.4 ° C. Over a period of 3 hours and 35 minutes, while the temperature is between 73.9 ° C and 82.2 ° C, 1440.98 parts of the above starting material are added. The reaction mixture is then heated to 85 ° C for 25 minutes and then maintained between 79.4 ° C and 86.1 ° C for 8 hours and 15 minutes. Then, the reaction mixture is cooled to 77.2 ° C over a period of 10 minutes and 5.92 parts of aqueous 90% formic acid is added. Next, the reaction mixture is cooled

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Over a period of 65 minutes to 54.4 ° C, 190 parts of liquid ortho-cresol are added.

The product, a phenol-formaldehyde resole resin / has a viscosity of 3500 mPa · s at 25 ° C.

5 (b) Foam Preparation.

A resole resin starting material is prepared by mixing equal parts of the two phenol-formaldehyde resin resins described above in parts (a) (i) and (a) (ii) and combining 67.1 parts of the resulting mixture with 2.4 parts surface active silicone agent "L-7003".

A catalyst starting material is prepared by mixing 10 parts aqueous 65% phenolic sulfonic acid, 6 parts aqueous 70% methanesulfonic acid, 1.5 parts aqueous 50% resorcinol and 15 parts part surfactant silicone "L-7003".

The resole resin starting material, catalyst starting material and a propellant containing 6 parts 1,1,2-trichloro-1, 2,2-trifluoroethane, 6 parts trichloromonofluoromethane and 1 part surfactant silicone agent "L-7003" are separately fed to and mixed in a distributor of a phenolic foam machine as schematically illustrated in FIG. 2nd

The resole resin starting material, catalyst starting material and propellant were kept at temperatures of 15.6-21.1 ° C, 15.6-18.3 ° C and 4.4 ° C, respectively, prior to mixing in the distributor.

The foamable material is continuously fed for 1 hour and 42 minutes to a lower abrasive sheet of sheet which is moved by the lower conveyor belt. An upper sheet of the same material and side papers coated with 30 polyethylene is fed to the machine directly in front of the cure cavity as illustrated in FIG. 2 and 3. For the next 1 hour and 10 minutes, the machine is stopped while the supply means is replaced. The machine is switched on again and foamy material is continuously fed for an additional 1 hour and 33 minutes.

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DK 169351 B1 29

The relative amounts of resole resin, catalyst and propellant in the foamable material are determined eight times during the operation for a total of 4 hours and 25 minutes (including the 1 hour and 10 minutes when the machine is stopped) and are as set forth below. Table VI.

Table vi

Total Time Sharing Drives

Time number elapsed Parts of resin Parts of catalyst _ means_ 10 l. 5 min. 72.9 16.2 10.9 2. 10 min. 71.9 16.8 11.3 3. 97 min. 68.2 20.7 11.1 4. 177 min. 67.4 21.0 11.6 5. 192 min. 68.9 20.4 10.8 15 6. 222 min. 67.0 21.6 11.4 7. 242 min. 62.6 25.8 11.6 8. 252 min. 63.6 25.6 10.8

During operation, the conveyor belt temperature 20 is maintained between 58.3 ° C and 67.2 ° C.

The foamable material is applied to the lower abutment material and the speed of the conveyor belt is adjusted so that once the foam is expanded to virtually fill the cure cavity, further expansion is prevented and pressure is created within the cure cavity.

A pressure measurement taken in the cure cavity after approx.

3 hours operation approx. 3/4 of the distance from the entrance to the cure cavity shows an excess pressure of 84 kPa created by the foam within the cavity. Temperature measurements for the foam, just after it exits the cure cavity, are taken during the first 3 hours and 2 minutes of operation and range from 96 ° C to 101 ° C.

Sixteen foam product samples were cut into groups of two, each group closely representing the foam fabric made from the foamable materials given for the eight times listed in Table VI. The initial heat conduction figures, the heat conduction figures after aging, and the core weights of the foam sample groups prepared from the eight foamable materials represented in Table VI are listed in Table VII below.

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Claims (4)

A process for preparing phenolic resin foams from a foamable phenolic resole resin material containing 40-90 wt.% Resole resin, 1-20 wt.% Of a propellant, 0.1-10 wt.% Of a surfactant, 2-40 wt.% water and 2-35 wt.% of a catalyst acid, characterized in that the foamable phenolic resole resin material is fed into a practically sealed volume in which the material is allowed to foam below 10 initially. atmospheric pressure until the foam virtually fills in said volume, where, within the practically closed volume, a pressure exceeding 35 kPa is obtained on the outer surface of the foam. Process according to claim 1, characterized in that the propellant is a mixture of trichloromonomofluoromethane and 1,1,2-trichloro-1,2,2-trifluoroethane. Process according to claim 1 or 2, characterized in that the phenolic resole resin is a phenol-aldehyde resole resin. 20 Process according to claim 3, characterized in that the aldehyde in the phenol-aldehyde resole resin is formaldehyde, paraformaldehyde or a mixture thereof.