CA1281866C - Process for the production of moldings of different elasticity or hardness from at least two liquid, foam- forming reaction mixtures - Google Patents
Process for the production of moldings of different elasticity or hardness from at least two liquid, foam- forming reaction mixturesInfo
- Publication number
- CA1281866C CA1281866C CA000550866A CA550866A CA1281866C CA 1281866 C CA1281866 C CA 1281866C CA 000550866 A CA000550866 A CA 000550866A CA 550866 A CA550866 A CA 550866A CA 1281866 C CA1281866 C CA 1281866C
- Authority
- CA
- Canada
- Prior art keywords
- mixture
- foam
- reaction mixture
- forming reaction
- production
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
- B29C44/0461—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by having different chemical compositions in different places, e.g. having different concentrations of foaming agent, feeding one composition after the other
- B29C44/0476—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by having different chemical compositions in different places, e.g. having different concentrations of foaming agent, feeding one composition after the other by pouring more than one composition into an open mould
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
- B29C44/0461—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by having different chemical compositions in different places, e.g. having different concentrations of foaming agent, feeding one composition after the other
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/58—Upholstery or cushions, e.g. vehicle upholstery or interior padding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/751—Mattresses, cushions
Landscapes
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Molding Of Porous Articles (AREA)
Abstract
A PROCESS FOR THE PRODUCTION OF MOLDINGS OF
DIFFERENT ELASTICITY OR HARDNESS FROM AT
LEAST TWO LIQUID, FOAM-FORMING REACTION MIXTURES
ABSTRACT OF THE DISCLOSURE
The present invention is directed to a process for the production of a molding from at least two different liquid foam-forming reaction mixtures comprising:
(i) introducing a first foam-forming reaction mixture into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
DIFFERENT ELASTICITY OR HARDNESS FROM AT
LEAST TWO LIQUID, FOAM-FORMING REACTION MIXTURES
ABSTRACT OF THE DISCLOSURE
The present invention is directed to a process for the production of a molding from at least two different liquid foam-forming reaction mixtures comprising:
(i) introducing a first foam-forming reaction mixture into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
Description
Mo-2993 LeA 24,844 A PROCESS FOR THE PRODUCTION OF MOLDINGS OF
DIFFERENT ELASTICITY OR HARDNESS FROM AT
LEAST TWO 5 LIQUID, FOAM-FORMING REACTION MI~TURES
BACKGROUND OF THE INVENTION
The present invention relates to a process for the production of moldings and more especially cushions of different elasticity or hardness from at least two liquid foam-forming reaction mixtures, more especially polyurethane foam reaction mixtures. A first and at least a second reaction mixture are introduced into a mold cavity and left to react to form a molding having zones of different elasticity or hardness before the molding is removed from the mold.
The production of moldings, particularly cushions, by in-mold foaming is gaining in popularity over the method of cutting to size because it i8 efficient and involves virtually no losses. The cushions can be subsequently provided with a fabric covering. Alternatively, the covering can be placed in a deep-draw die and directly back-foamed.
Various processes have been proposed for the production of moldings having zones of different hardness. According to EP-Bl-68,820, a second foam mixture is directly introduced onto a first foam mixture at a time corresponding to an expansion in volume of the first mixture of ~100% to ~2300%. One or more relatively hard zones are thus formed within a relatively sot foam. In this process, the second reaction mixture cannot be introduced until the first reaction mixture has undergone the necessary expansion in volume. The cycle times of the foaming process are thus undesirably lengthened. In addition, the actual objective, namely covering relatively hard zones with a layer of soft foam to increase comfort, is di~ficult to Mo-2993 LB~
achieve because the expansion of the soft layer remains limited in certain zones to only narrow thicknesses which only inadequately impart the desired properties.
In addition, difficulties also arise with regard to the 5 reproducibility of these coverings.
In another process (U.S. Patent 4,190,697), a mixture forming a relatively hard foam is fi~st introduced into the mold where it is allowed to begin foaming. Afterwards, a second mixture forming so~ter 10 foam is introduced when the first mixture has reached 10 to 80% o its full foaming capacity. The second mixture permeates the first mixture during introduction and causes it to swell. Both mixtures then react and form a polyurethane foam article having zones of different 15 density. The disadvantage of this process is that the permeation and underflow of the first reaction mixture is irregular so that the properties (and, primarily the indentation hardness) of the moldings obtained are not sufficiently reproducible.
Accordingly, the object of the present invention was to provide a process which makes shorter cycle times possible for good reproducibility in the development of the zones of different hardness or elasticity.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 and 2 illustrate the production of a seat cushion.
Figure 3 shows the finished seat cushion.
Figures 4 to 10 show further embodiments of 30 seat cushions with side webs which can be produced by the new process.
Figure 11 is a longitudinal section through a seat cushion having foam zones of three dif~erent hardnesses.
Mo-2993 - 2 -L21 3~ !366 DESCRIPTION OF THE INVENTION
According to the invention, the above object is achieved in that, on introduction into the mold, the second reac~ion mixture is allowed to cream up to such 5 an extent that, by the time it comes into contact with ~he first reaction mixture, it already has a lower density than the first reaction mixture. The second or further reaction mixture(s) is introduced onto and/or next to the layer(s) formed by the first or further 10 reaction mixture(s).
More particularly, the present invention is directed to a process for the production of a molding from at least two different liquid foam-forming reaction mixtures comprising: 5 (i) introducing a first foam-forming reaction mix~ure into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
In this way, any formulation may be used for the first reaction mixture which opens up new applications because, through the introduction of the second or further reaction mixture(s) with correspond-ingly lower density, the course of the process is made 35 largely independent of the state of the first reaction mixture at the moment it is contacted by the second.
Mo-2993 - 3 -- ~2~3~L86~i Another effect is that 9 on contact with the first mixture by overflowing from the side or by direct application to the layer of the first mixture, no turbulence is generated so long as the force of impact 5 is not too great. In other words, the introduc~ion of ~he second mixture has to be carried out with some care.
On the other hand, even the mixing units widely in use today guarantee sufficiently low discharge rates to avoid turbulence of the various reaction mixtures.
10 Where a third or further reaction mix~ure(s) is/are introduced, this/these mixture(s) hasthave to be balanced in regard to its/their creamy consistency in such a way that, at the moment of contact with one of the other reaction mixtures, it ~eets the lower density 15 requirement.
The second or further reaction mixture(s) may be introduced at the same time as or after the first or other reaction mixture, depending on requirements.
Simultaneous introduction is advisable in particular 20 when the various reaction mixtures are introduced into various regions. In this connection, it is quite possible to charge two regions separated for example by a third region with the same reaction mixture while the region lying in between is charged with another reaction 25 mixture. If it is desired to in~roduce another reaction mixture directly onto a first reaction mixture, it is best to do this after an appropriate time interval so that the mixture previously introduced has already spread out extensively over the region in question.
Where and when the softer or the harder foam-forming reaction mixture is introduced first or whether the two are introduced at the same time depends on various factors, but primarily on where in the mold cavity the corresponding zones of different hardness are 35 to form.
Mo-2993 - 4 -~ 6 In particular, it is possible by the new process to obtain rigid zones covered on one side or all sides with layers of any thickness of flexible foam or vice versa. Since the second reaction mixture, through 5 its creamy consistency, may have reached its maximum degree of foaming before the first reaction mixture (providing appropriate activators are used), it is possible for the still relatively liquid first reaction mixture to be laterally forced upwards at least to a 10 certain level or even completely to surround the foam formed by the second reaction mixture. Such partial or complete coverage in any desired thickness may readily be determined by tests and depends largely on the geometry of the molding or mold cavity and on ~he 15 quantities involved.
Suitable raw materials for the production of the moldings in question are, in particular, any of the usual polyurethane foam systems (cf. also Kunststoff-Handbuch, Vol. VII, Polyurethane, by Vieweg and 20 Hochtlen, ~arl-Hanser-Verlag, Munchen 1966, in particular pp. 440-503 and 569-571). The differences in hardness between the individual reaction mixtures are generally adjustable through index variation and/or through the formulations, for example through the filler 25 content, crosslinker variation, gross density ratio, and the like. The rapid creaming of the second mixture is obtained by adding to this formulation additives which, when the components are mixed, spontaneously evo~ve CO2 or any other compound gaseous under the reaction 30 conditions. The amine-carbon dioxide adducts described in EP-A-121,850 are preferably used. However, it is also possible to produce a froth foam. The creaming can also be effected or accelerated by loading one o~ the reaction components with gas, and in particular with an 35 inert gas such as CO2 or N2. The component can be charged with gas at various gas pressures by Mo-2993 ~ 5 ~
substantially any dissolving or dispersing means.
Another possibility is to prepare the second reaction mix~ure correspondingly early, i.e. to introduce it with delay so that it has already acquired the necessary 5 lower density by the time it comes into contact with the first mixture. In this sense, the second reaction mixture may be prepared even earlier than the first so that it may be introduced, for example, at the same time or immediately after the first mixture has spread out to 10 form a layer.
The process according to the invention is particularly suitable for the production of vehicle seat cushions having side webs. The novel aspect of this particular application is that a first foam-forming 15 reaction mixture is poured into those parts of the mold cavity corresponding to the webs and onto that part corresponding to the seat surface, followed by at least a second foam-forming reaction mixture so advance in its expansion that, by the time it comes into contact with 20 the layers of the first reaction mixture, it has already acquired a lower density than the first reaction mixture so that, at best, it sinks in but does not permeate the first layer. In this way, it is possible to produce both uncovered seat cushions and also those having ! 25 back-foamed coverings. Through the use of several mixing heads for preparing the same reaction mixture or different reaction mixtures, the new process may be varied very widely in its application.
The new process is illustrated by a practical 30 example of its application for the production of a cushion for vehicle seats in conjunction with the drawin~s.
The new process can be used to produce a seat cushion of the type shown in Figure 3 with side webs 1, 35 2 and seat section 3. The outer zones 4, 5 of the side webs consist of a relatively hard ~oam, e.g., one having Mo-2993 - 6 -28~L86~
a density of 50 kg/dm3 and a compression hardness according to DIN 53 577 of 7.3 kPa. The seat section 3 is separated from the side webs 1, 2 by grooves 6, 7. A
zone 8 of relati~ely soft foam, e.g., one having a 5 density of 50 kg/dm3 and a compression hardness of 3.3 kPa, extends over the seat section 3 beyond the grooves 6, 7 into the side webs 1, 2 and forms a firm, but clearly defined union with the zones 4, 5. The to~al volume of the seat cushion is, e.g., 32 dm3 of which, 10 e.g., 25 dm3 is occupied by the softer foam corresponding to the zone 8.
The seat cushion is produced as shown in Figures 1 and 2. The mold 11 has a cavity 12 which 15 represents the seat cushion upside down, as also shown in Figure 3. The regions 13, 14 correspond to the side webs 1, 2, the region 15 to the seat section 3 and the dividers 16, 17 to the grooves 6, 7 of the seat cushion.
By means of two mixing heads 18, 19 (Figure 1), the 20 reaction mixture forming the softer foam is introduced into each of the two side web regions 13, 14 in a quantity of e.g., 180 g. Thereafter (Figure 2), the mixing heads 18, 19 are placed over the seat region 15 where the same reaction mixture is introduced in a 25 quantity of, e.g., 1150 g. The dividers 16, 17 prevent the reaction mixture from flowing off into the side web regions 13, 14. By means of two mixing heads 20, 21, the reaction mixture forming the harder foam is introduced ont the first reaction mixture already 30 present in the side web regions 13, 14 at the same time as the seat region 15 i8 being filled by the mixing heads 18, 19. The density of the first reaction mixture at the moment of contact with the second reaction mixture is, e.g., 0.8 kg/dm3 while the second reaction 35 mixture is introduced in such a creamed statè that it has a lower density of, e.g., 0.3 kg/dm3, at the moment Mo-2993 - 7 -~2~31816~;
. ~
of contact with the first reaction mixture~ The time delay between the ~eginning of introduction of the first reaction mixtùre and contact by the second is in the case of the numbers exemplified abo~e 7 seconds. After 5 closure of the mold 11, the reaction mixtures foam completely to form the seat cushion shown in Figure 3.
In the case of ~arious numbers exemplified above, the first reaction mixture forming the softer foam had the following formulation (pbw = parts by 10 weight):
Component A
100 pbw of a polyether obtained by addition of propylene oxide and then ethylene oxide to trimethylol propane, having a functionality of 3, a primary OH content of about 80% by weight and an OH number of about 30;
3.1 pbw water;
0.2 pbw bis-dimethylaminoethylether;
0.4 pbw of a commercial foam stabilizer consisting of a mixture of low molecular weight siloxanes (Stabilisator KS 43, a product of BAYER AG, Leverkusen, Fed. Rep. of Germany);
0.8 pbw triethylene diamine (33Z in dipropylene glycol).
25 Component B
45.3 pbw of an isocyanate containing approx. 65Z by weight 4,4'-dimethylmethane diisocyanate and approx. 20% by weight 2,4'-diphenyl methane diisocyanate and approx. 15Z by weight polymeric MDI; NCO content approx. 32.5Z. Components A and B were mixed at an NCO index of 85.
The second reaction mixture forming the harder foam had the following formulation:
Mo-2993 - 8 -_ ~Z ~ ~ 6 Component A
100 pbw of a polyether obtained by addition of propylene oxide and then ethylene oxide to trimethylol propane, having a functionality of 3, a primary OH content of about 80% by weight and an OH number of about 30;
3.1 pbw water;
0.2 pbw bis-dimethylaminoethylether;
0.4 pbw commercial foam stabilizPr consisting of a mixture of low molecular weight siloxanes (Stabilisator KS 43, a product of Bayer AG, Leverkusen, Fed. Rep. of Germany);
0.8 pbw triethylenediamine (33Z in dipropylene glycol);
15 4.0 pbw of the adduct of C02 with N-methyl ethanolamine.
Component B
70.6 pbw of an isocyanate containing approx. 65% by weight 4,4'-diphenylmethane diisocyanate and approx. 20% by weight 2,4'-diphenylmethane diisocyanate and approx. 15~ by weight polymeric MDI for an NCO content of approx. 32.5Z.
Components A and B were mixed at an NCO index of 110 .
In the other embodiments of seat cushions produced by the new process which are shown in Figures 4 to 10 (in section in the normal position), the zones of softer foam are hatched at broad intervals while the zones of harder foam are hatched at narrow intervals.
In Figure 11, the seat section consis~s of a ioam of medium hardness (which i8 also at the back of the knees). On the underneath of the seat cushion, however, there is a very soft zone. The third zone is the hardest.
Mo-2993 - 9 --- ~2 ~L~ ~
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by 5 those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo-2993 - 10 -
DIFFERENT ELASTICITY OR HARDNESS FROM AT
LEAST TWO 5 LIQUID, FOAM-FORMING REACTION MI~TURES
BACKGROUND OF THE INVENTION
The present invention relates to a process for the production of moldings and more especially cushions of different elasticity or hardness from at least two liquid foam-forming reaction mixtures, more especially polyurethane foam reaction mixtures. A first and at least a second reaction mixture are introduced into a mold cavity and left to react to form a molding having zones of different elasticity or hardness before the molding is removed from the mold.
The production of moldings, particularly cushions, by in-mold foaming is gaining in popularity over the method of cutting to size because it i8 efficient and involves virtually no losses. The cushions can be subsequently provided with a fabric covering. Alternatively, the covering can be placed in a deep-draw die and directly back-foamed.
Various processes have been proposed for the production of moldings having zones of different hardness. According to EP-Bl-68,820, a second foam mixture is directly introduced onto a first foam mixture at a time corresponding to an expansion in volume of the first mixture of ~100% to ~2300%. One or more relatively hard zones are thus formed within a relatively sot foam. In this process, the second reaction mixture cannot be introduced until the first reaction mixture has undergone the necessary expansion in volume. The cycle times of the foaming process are thus undesirably lengthened. In addition, the actual objective, namely covering relatively hard zones with a layer of soft foam to increase comfort, is di~ficult to Mo-2993 LB~
achieve because the expansion of the soft layer remains limited in certain zones to only narrow thicknesses which only inadequately impart the desired properties.
In addition, difficulties also arise with regard to the 5 reproducibility of these coverings.
In another process (U.S. Patent 4,190,697), a mixture forming a relatively hard foam is fi~st introduced into the mold where it is allowed to begin foaming. Afterwards, a second mixture forming so~ter 10 foam is introduced when the first mixture has reached 10 to 80% o its full foaming capacity. The second mixture permeates the first mixture during introduction and causes it to swell. Both mixtures then react and form a polyurethane foam article having zones of different 15 density. The disadvantage of this process is that the permeation and underflow of the first reaction mixture is irregular so that the properties (and, primarily the indentation hardness) of the moldings obtained are not sufficiently reproducible.
Accordingly, the object of the present invention was to provide a process which makes shorter cycle times possible for good reproducibility in the development of the zones of different hardness or elasticity.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 and 2 illustrate the production of a seat cushion.
Figure 3 shows the finished seat cushion.
Figures 4 to 10 show further embodiments of 30 seat cushions with side webs which can be produced by the new process.
Figure 11 is a longitudinal section through a seat cushion having foam zones of three dif~erent hardnesses.
Mo-2993 - 2 -L21 3~ !366 DESCRIPTION OF THE INVENTION
According to the invention, the above object is achieved in that, on introduction into the mold, the second reac~ion mixture is allowed to cream up to such 5 an extent that, by the time it comes into contact with ~he first reaction mixture, it already has a lower density than the first reaction mixture. The second or further reaction mixture(s) is introduced onto and/or next to the layer(s) formed by the first or further 10 reaction mixture(s).
More particularly, the present invention is directed to a process for the production of a molding from at least two different liquid foam-forming reaction mixtures comprising: 5 (i) introducing a first foam-forming reaction mix~ure into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
In this way, any formulation may be used for the first reaction mixture which opens up new applications because, through the introduction of the second or further reaction mixture(s) with correspond-ingly lower density, the course of the process is made 35 largely independent of the state of the first reaction mixture at the moment it is contacted by the second.
Mo-2993 - 3 -- ~2~3~L86~i Another effect is that 9 on contact with the first mixture by overflowing from the side or by direct application to the layer of the first mixture, no turbulence is generated so long as the force of impact 5 is not too great. In other words, the introduc~ion of ~he second mixture has to be carried out with some care.
On the other hand, even the mixing units widely in use today guarantee sufficiently low discharge rates to avoid turbulence of the various reaction mixtures.
10 Where a third or further reaction mix~ure(s) is/are introduced, this/these mixture(s) hasthave to be balanced in regard to its/their creamy consistency in such a way that, at the moment of contact with one of the other reaction mixtures, it ~eets the lower density 15 requirement.
The second or further reaction mixture(s) may be introduced at the same time as or after the first or other reaction mixture, depending on requirements.
Simultaneous introduction is advisable in particular 20 when the various reaction mixtures are introduced into various regions. In this connection, it is quite possible to charge two regions separated for example by a third region with the same reaction mixture while the region lying in between is charged with another reaction 25 mixture. If it is desired to in~roduce another reaction mixture directly onto a first reaction mixture, it is best to do this after an appropriate time interval so that the mixture previously introduced has already spread out extensively over the region in question.
Where and when the softer or the harder foam-forming reaction mixture is introduced first or whether the two are introduced at the same time depends on various factors, but primarily on where in the mold cavity the corresponding zones of different hardness are 35 to form.
Mo-2993 - 4 -~ 6 In particular, it is possible by the new process to obtain rigid zones covered on one side or all sides with layers of any thickness of flexible foam or vice versa. Since the second reaction mixture, through 5 its creamy consistency, may have reached its maximum degree of foaming before the first reaction mixture (providing appropriate activators are used), it is possible for the still relatively liquid first reaction mixture to be laterally forced upwards at least to a 10 certain level or even completely to surround the foam formed by the second reaction mixture. Such partial or complete coverage in any desired thickness may readily be determined by tests and depends largely on the geometry of the molding or mold cavity and on ~he 15 quantities involved.
Suitable raw materials for the production of the moldings in question are, in particular, any of the usual polyurethane foam systems (cf. also Kunststoff-Handbuch, Vol. VII, Polyurethane, by Vieweg and 20 Hochtlen, ~arl-Hanser-Verlag, Munchen 1966, in particular pp. 440-503 and 569-571). The differences in hardness between the individual reaction mixtures are generally adjustable through index variation and/or through the formulations, for example through the filler 25 content, crosslinker variation, gross density ratio, and the like. The rapid creaming of the second mixture is obtained by adding to this formulation additives which, when the components are mixed, spontaneously evo~ve CO2 or any other compound gaseous under the reaction 30 conditions. The amine-carbon dioxide adducts described in EP-A-121,850 are preferably used. However, it is also possible to produce a froth foam. The creaming can also be effected or accelerated by loading one o~ the reaction components with gas, and in particular with an 35 inert gas such as CO2 or N2. The component can be charged with gas at various gas pressures by Mo-2993 ~ 5 ~
substantially any dissolving or dispersing means.
Another possibility is to prepare the second reaction mix~ure correspondingly early, i.e. to introduce it with delay so that it has already acquired the necessary 5 lower density by the time it comes into contact with the first mixture. In this sense, the second reaction mixture may be prepared even earlier than the first so that it may be introduced, for example, at the same time or immediately after the first mixture has spread out to 10 form a layer.
The process according to the invention is particularly suitable for the production of vehicle seat cushions having side webs. The novel aspect of this particular application is that a first foam-forming 15 reaction mixture is poured into those parts of the mold cavity corresponding to the webs and onto that part corresponding to the seat surface, followed by at least a second foam-forming reaction mixture so advance in its expansion that, by the time it comes into contact with 20 the layers of the first reaction mixture, it has already acquired a lower density than the first reaction mixture so that, at best, it sinks in but does not permeate the first layer. In this way, it is possible to produce both uncovered seat cushions and also those having ! 25 back-foamed coverings. Through the use of several mixing heads for preparing the same reaction mixture or different reaction mixtures, the new process may be varied very widely in its application.
The new process is illustrated by a practical 30 example of its application for the production of a cushion for vehicle seats in conjunction with the drawin~s.
The new process can be used to produce a seat cushion of the type shown in Figure 3 with side webs 1, 35 2 and seat section 3. The outer zones 4, 5 of the side webs consist of a relatively hard ~oam, e.g., one having Mo-2993 - 6 -28~L86~
a density of 50 kg/dm3 and a compression hardness according to DIN 53 577 of 7.3 kPa. The seat section 3 is separated from the side webs 1, 2 by grooves 6, 7. A
zone 8 of relati~ely soft foam, e.g., one having a 5 density of 50 kg/dm3 and a compression hardness of 3.3 kPa, extends over the seat section 3 beyond the grooves 6, 7 into the side webs 1, 2 and forms a firm, but clearly defined union with the zones 4, 5. The to~al volume of the seat cushion is, e.g., 32 dm3 of which, 10 e.g., 25 dm3 is occupied by the softer foam corresponding to the zone 8.
The seat cushion is produced as shown in Figures 1 and 2. The mold 11 has a cavity 12 which 15 represents the seat cushion upside down, as also shown in Figure 3. The regions 13, 14 correspond to the side webs 1, 2, the region 15 to the seat section 3 and the dividers 16, 17 to the grooves 6, 7 of the seat cushion.
By means of two mixing heads 18, 19 (Figure 1), the 20 reaction mixture forming the softer foam is introduced into each of the two side web regions 13, 14 in a quantity of e.g., 180 g. Thereafter (Figure 2), the mixing heads 18, 19 are placed over the seat region 15 where the same reaction mixture is introduced in a 25 quantity of, e.g., 1150 g. The dividers 16, 17 prevent the reaction mixture from flowing off into the side web regions 13, 14. By means of two mixing heads 20, 21, the reaction mixture forming the harder foam is introduced ont the first reaction mixture already 30 present in the side web regions 13, 14 at the same time as the seat region 15 i8 being filled by the mixing heads 18, 19. The density of the first reaction mixture at the moment of contact with the second reaction mixture is, e.g., 0.8 kg/dm3 while the second reaction 35 mixture is introduced in such a creamed statè that it has a lower density of, e.g., 0.3 kg/dm3, at the moment Mo-2993 - 7 -~2~31816~;
. ~
of contact with the first reaction mixture~ The time delay between the ~eginning of introduction of the first reaction mixtùre and contact by the second is in the case of the numbers exemplified abo~e 7 seconds. After 5 closure of the mold 11, the reaction mixtures foam completely to form the seat cushion shown in Figure 3.
In the case of ~arious numbers exemplified above, the first reaction mixture forming the softer foam had the following formulation (pbw = parts by 10 weight):
Component A
100 pbw of a polyether obtained by addition of propylene oxide and then ethylene oxide to trimethylol propane, having a functionality of 3, a primary OH content of about 80% by weight and an OH number of about 30;
3.1 pbw water;
0.2 pbw bis-dimethylaminoethylether;
0.4 pbw of a commercial foam stabilizer consisting of a mixture of low molecular weight siloxanes (Stabilisator KS 43, a product of BAYER AG, Leverkusen, Fed. Rep. of Germany);
0.8 pbw triethylene diamine (33Z in dipropylene glycol).
25 Component B
45.3 pbw of an isocyanate containing approx. 65Z by weight 4,4'-dimethylmethane diisocyanate and approx. 20% by weight 2,4'-diphenyl methane diisocyanate and approx. 15Z by weight polymeric MDI; NCO content approx. 32.5Z. Components A and B were mixed at an NCO index of 85.
The second reaction mixture forming the harder foam had the following formulation:
Mo-2993 - 8 -_ ~Z ~ ~ 6 Component A
100 pbw of a polyether obtained by addition of propylene oxide and then ethylene oxide to trimethylol propane, having a functionality of 3, a primary OH content of about 80% by weight and an OH number of about 30;
3.1 pbw water;
0.2 pbw bis-dimethylaminoethylether;
0.4 pbw commercial foam stabilizPr consisting of a mixture of low molecular weight siloxanes (Stabilisator KS 43, a product of Bayer AG, Leverkusen, Fed. Rep. of Germany);
0.8 pbw triethylenediamine (33Z in dipropylene glycol);
15 4.0 pbw of the adduct of C02 with N-methyl ethanolamine.
Component B
70.6 pbw of an isocyanate containing approx. 65% by weight 4,4'-diphenylmethane diisocyanate and approx. 20% by weight 2,4'-diphenylmethane diisocyanate and approx. 15~ by weight polymeric MDI for an NCO content of approx. 32.5Z.
Components A and B were mixed at an NCO index of 110 .
In the other embodiments of seat cushions produced by the new process which are shown in Figures 4 to 10 (in section in the normal position), the zones of softer foam are hatched at broad intervals while the zones of harder foam are hatched at narrow intervals.
In Figure 11, the seat section consis~s of a ioam of medium hardness (which i8 also at the back of the knees). On the underneath of the seat cushion, however, there is a very soft zone. The third zone is the hardest.
Mo-2993 - 9 --- ~2 ~L~ ~
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by 5 those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo-2993 - 10 -
Claims (3)
1. A process for the production of a molding from at least two different liquid foam-forming reaction mixtures comprising:
(i) introducing a first foam-forming reaction mixture into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
(i) introducing a first foam-forming reaction mixture into a mold, (ii) introducing a second foam-forming reaction mixture onto and/or next to the layer formed by said first reaction mixture, the introduction of said second mixture being such that said second mixture is so advanced in its expansion that by the time it contacts said first mixture, said second mixture already has a lower density than said first mixture, (iii) allowing said reaction mixture to react to form a molding having zones of different elasticity or hardeness, and (iv) removing said molding from said mold.
2. The process of Claim 1 wherein steps i) and ii) occur substantially simultaneously.
3. The process of Claim 1 wherein said first reaction mixture is introduced into the regions of said mold corresponding to the side webs and onto the region corresponding to the seat area of a cushion.
Mo-2993
Mo-2993
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19863638205 DE3638205A1 (en) | 1986-11-08 | 1986-11-08 | METHOD FOR PRODUCING MOLDED PARTS, ESPECIALLY UPHOLSTERY, FROM AT LEAST TWO FOAMS, IN PARTICULAR POLYURETHANE FOAMS, DIFFERENT ELASTICITY OR. HARDENING, FLOWABLE REACTION MIXTURES AND APPLICATION OF THIS METHOD FOR THE PRODUCTION OF VEHICLE SEAT PADS WITH SIDE CURVES |
| DEP3638205.1 | 1986-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1281866C true CA1281866C (en) | 1991-03-26 |
Family
ID=6313535
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000550866A Expired - Lifetime CA1281866C (en) | 1986-11-08 | 1987-11-03 | Process for the production of moldings of different elasticity or hardness from at least two liquid, foam- forming reaction mixtures |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0267490B1 (en) |
| JP (1) | JPS63172614A (en) |
| KR (1) | KR880006037A (en) |
| AU (1) | AU600042B2 (en) |
| BR (1) | BR8705970A (en) |
| CA (1) | CA1281866C (en) |
| DE (2) | DE3638205A1 (en) |
| ES (1) | ES2012793B3 (en) |
| ZA (1) | ZA878337B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180290347A1 (en) * | 2011-11-28 | 2018-10-11 | Ford Global Technologies, Llc | Dual firmness head restraint |
| CN109843960A (en) * | 2016-10-28 | 2019-06-04 | 科思创德国股份有限公司 | Process for producing polyurethane foam molded article |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4755411A (en) * | 1987-04-22 | 1988-07-05 | Milsco Limited | Cushion having flexible outer membrane and multi-density resilient foam member therein |
| DE3727131A1 (en) * | 1987-08-14 | 1989-02-23 | Bayer Ag | METHOD FOR PRODUCING FOAM PADS FROM AT LEAST TWO FOAMS, ESPECIALLY POLYURETHANE FOAMS, DIFFERENT ELASTICITY OR. HARD EDUCATIONAL, FLOWABLE, ACCORDINGLY DIFFERENT REACTION MIXTURES |
| DE3727129A1 (en) * | 1987-08-14 | 1989-02-23 | Bayer Ag | METHOD FOR PRODUCING FOAM PADS FROM AT LEAST TWO FOAMS, ESPECIALLY POLYURETHANE FOAMS, DIFFERENT ELASTICITY OR. HARD EDUCATIONAL, FLOWABLE, ACCORDINGLY DIFFERENT REACTION MIXTURES |
| GB8827280D0 (en) * | 1988-11-22 | 1988-12-29 | Bp Chem Int Ltd | Process for making polyurethane foam |
| GB8906297D0 (en) * | 1989-03-18 | 1989-05-04 | Bp Chem Int Ltd | Process for preparing multihardness foam articles |
| US5244612A (en) * | 1989-12-08 | 1993-09-14 | Bridgestone Corporation | Method for molding polyurethane seat paddings |
| DE4002067A1 (en) * | 1990-01-25 | 1991-08-14 | Basf Ag | LAMINATES WITH IMPROVED EDGE STABILITY |
| GB9625594D0 (en) | 1996-12-10 | 1997-01-29 | Polyol Int Bv | Process for manufacturing multilayered foam articles |
| DE19751091A1 (en) * | 1997-11-18 | 1999-05-20 | Bayerische Motoren Werke Ag | Vehicle seat with modular upholstery |
| WO2009105059A1 (en) * | 2008-02-19 | 2009-08-27 | Johnson Controls Technology Company | Foam cushion |
| US9420891B2 (en) * | 2013-11-29 | 2016-08-23 | Zinus, Inc. | Foam furniture molded around a rigid foam core |
| DE102013020488A1 (en) * | 2013-12-11 | 2015-06-11 | Heyform Bramsche Gmbh | Method for producing a sandwich composite component |
| AT519381A2 (en) * | 2016-11-24 | 2018-06-15 | Fill Gmbh | Process for producing a shaped body |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1014232B (en) * | 1974-05-28 | 1977-04-20 | Stars Spa | PROCEDURE FOR THE MANUFACTURING OF AN EXPANDED SYNTHETIC RESIN PADDING FOR PARTICULARLY SEATS OF MOTOR VEHICLES |
| DD113475A1 (en) * | 1974-06-25 | 1975-06-12 | ||
| US4073020A (en) * | 1976-04-19 | 1978-02-14 | The Goodyear Tire & Rubber Company | Contoured foam mattress |
| CA1194660A (en) * | 1981-06-27 | 1985-10-08 | Rudolf J. Tenhagen | Process for making polyurethane foam |
| GB8616132D0 (en) * | 1986-07-02 | 1986-08-06 | Bp Chem Int Ltd | Polyurethane foams |
-
1986
- 1986-11-08 DE DE19863638205 patent/DE3638205A1/en not_active Withdrawn
-
1987
- 1987-10-27 DE DE8787115756T patent/DE3761189D1/en not_active Expired - Lifetime
- 1987-10-27 ES ES87115756T patent/ES2012793B3/en not_active Expired - Lifetime
- 1987-10-27 EP EP87115756A patent/EP0267490B1/en not_active Expired
- 1987-11-03 CA CA000550866A patent/CA1281866C/en not_active Expired - Lifetime
- 1987-11-03 AU AU80690/87A patent/AU600042B2/en not_active Ceased
- 1987-11-06 JP JP62279478A patent/JPS63172614A/en active Pending
- 1987-11-06 ZA ZA878337A patent/ZA878337B/en unknown
- 1987-11-06 BR BR8705970A patent/BR8705970A/en unknown
- 1987-11-07 KR KR870012566A patent/KR880006037A/en not_active Application Discontinuation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180290347A1 (en) * | 2011-11-28 | 2018-10-11 | Ford Global Technologies, Llc | Dual firmness head restraint |
| US11904512B2 (en) * | 2011-11-28 | 2024-02-20 | Ford Global Technologies, Llc | Dual firmness head restraint |
| CN109843960A (en) * | 2016-10-28 | 2019-06-04 | 科思创德国股份有限公司 | Process for producing polyurethane foam molded article |
| CN109843960B (en) * | 2016-10-28 | 2021-08-10 | 科思创德国股份有限公司 | Process for producing polyurethane foam molded article |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3638205A1 (en) | 1988-05-11 |
| AU8069087A (en) | 1988-05-12 |
| AU600042B2 (en) | 1990-08-02 |
| KR880006037A (en) | 1988-07-21 |
| JPS63172614A (en) | 1988-07-16 |
| ES2012793B3 (en) | 1990-04-16 |
| BR8705970A (en) | 1988-06-14 |
| EP0267490B1 (en) | 1989-12-20 |
| ZA878337B (en) | 1988-05-03 |
| DE3761189D1 (en) | 1990-01-25 |
| EP0267490A1 (en) | 1988-05-18 |
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Legal Events
| Date | Code | Title | Description |
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| MKLA | Lapsed |