BCHPC Having a Reduced Burning Rate

Abstract

The invention relates to the reduction of the burning rate of di-(4-tert-butylcyclohexyl)-peroxydicarbonate (BCHPC) by adding desensitizers as well as to the use of BCHPC preparations having a reduced burning rate as an initiator in chemical reactions.

Claims

1. Use of at least one organic peroxide and/or desensitising agent for reducing the burning rate of di-(4-tert-butylcyclohexyl)-peroxydicarbonate (BCHPC), comprising provision of a mixture that comprises BCHPC and at least one further organic peroxide and/or at least one desensitising agent, wherein the at least one desensitising agent is an inert solid towards BCHPC.

2. Use according to claim 1, wherein the mixture is present in solid form, preferably in powder form.

3. Use according to either claim 1 or claim 2, wherein at least one organic peroxide is used, which is selected from dilauroyl peroxide (LP), dicetyl peroxydicarbonate (CEPC) and dimyristyl peroxydicarbonate (MYPC).

4. Use according to any of the preceding claims, wherein at least one desensitising agent is used, which is selected from dicyclohexyl phthalate, fluorene, aluminium trihydroxide, polystyrene and glyceryl tribenzoate.

5. Use according to any of the preceding claims, wherein the proportion of BCHPC relative to the mixture of BCHPC and further organic peroxide and/or desensitising agent is 10 to 90 wt. %, preferably 25 to 75 wt. % or 30 to 60 wt. %.

6. Use according to any of the preceding claims, wherein the ratio of BCHPC to further organic peroxide is 10:90 to 90:10 wt. %, preferably 25:75 to 75:25 wt. % or 40:60 to 60:40 wt. %.

7. Use according to any of the preceding claims, wherein the ratio of BCHPC to desensitising agent is 10:90 to 90:10 wt. %, preferably 25:75 to 75:25 wt. % or 40:60 to 60:40 wt. %.

8. Use according to any of the preceding claims, wherein the mixture further comprises polymers or inorganic or organic fillers.

9. Use according to any of the preceding claims, comprising the steps of (i) mixing BCHPC with the at least one further organic peroxide, wherein BCHPC is present in solid form, in the form of a solution in an organic solvent or in the form of an aqueous suspension and the at least one further organic peroxide is present in solid form, in the form of a solution in an organic solvent or in the form of an aqueous suspension, (ii) optional removal of solvent and/or water and (iii) optional drying.

10. Use according to claim 1, wherein the at least one organic peroxide in solid form or in the form of an aqueous suspension is mixed with BCHPC in solid form or in the form of an aqueous suspension and water is then optionally removed.

11. Use according to any of the preceding claims, wherein the at least one further organic peroxide and the BCHPC are mixed in dry or water-moistened solid form.

12. Use according to any of claims 1 to 8, comprising the steps of (i) mixing BCHPC with the at least one desensitising agent, wherein BCHPC is present in solid form, in the form of a solution in an organic solvent or in the form of an aqueous suspension, and the at least one desensitising agent is present in solid form, as a melt or in the form of a solution or suspension in an organic or aqueous solvent, (ii) optional removal of solvent and/or water and (iii) optional drying.

13. Use according to any of claims 1 to 8, comprising the steps of (i) dissolving the at least one desensitising agent in a precursor of BCHPC, for example butylcyclohexyl chloroformate, or in an aqueous solution or suspension of the precursor of BCHPC, (ii) reacting the solution obtained with a mixture of aqueous hydrogen peroxide and sodium hydroxide solution, (iii) separating the resulting BCHPC/desensitising agent mixture, and (iv) optional drying.

14. Composition, comprising BCHPC and at least one substance for reducing the burning rate, wherein the substance for reducing the burning rate is selected from organic peroxides, desensitising agents and mixtures thereof.

15. Use of a composition according to claim 14 as an initiator in a chemical reaction, in particular in a method for curing e.g. an unsaturated polyester resin.

Description

[0062] The invention will be illustrated further by the following figures and examples.

[0063] FIG. 1: Burning rate of BCHPC compared to different BCHPC preparations having desensitising agents. Preparations of BCHPC having CUROX LP-S, glyceryl tribenzoate, CUROX CC-DC, aluminium trihydroxide, polystyrene, dicyclohexyl phthalate, or fluorene are shown.

[0064] FIG. 2: Burning rate of BCHPC having dicyclohexyl phthalate in different mixing ratios.

[0065] FIG. 3: Burning rates of BCHPC preparations having various organic peroxides.

[0066] FIG. 3A shows preparations of BCHPC having CUROX LP-S in various mixing ratios in comparison with pure CUROX LP-S and BCHPC.

[0067] FIG. 3B shows the results for mixtures of BCHPC with CEPC 65% in various mixing ratios, and for mixtures of BCHPC with MYPC or with a combination of CUROX LP-S and MYPC, compared to pure BCHPC.

[0068] FIG. 4: Temperature profile during the curing having various BCHPC preparations. Shown are the results for dry BCHPC (BCHPC), water-moistened BCHPC (BCHPC-75-W), dry CEPC (CEPC), water-moistened CEPC 65%, and for combinations of dry BCHPC with CUROX LP-S, CEPC 65% or CUROX LP-S and MYPC.

EXAMPLES

[0069] 1. Analysis of the Burning Rate

[0070] 1.1 Combination of BCHPC with Different Desensitising Agents

[0071] Various mixtures of BCHPC were produced having different desensitising agents and analysed with regard to their burning rates.

[0072] The following combinations of BCHPC with peroxide or desensitising agents were analysed:

[0073] BCHPC: CUROX LP-S(2:1)

[0074] BCHPC: Glyceryl tribenzoate (2:1)

[0075] BCHPC: CUROX CC-DC (2:1)

[0076] BCHPC: Aluminium trihydroxide (2:1)

[0077] BCHPC: Polystyrene (2:1)

[0078] BCHPC: Dicyclohexyl phthalate (2:1)

[0079] BCHPC: Fluorene (2:1)

[0080] BCHPC

[0081] The indications of the quantity ratios describe weight ratios in each case.

[0082] CUROX LP-S is a 75 to 80%, water-moistened dilauroyl peroxide from United Initiators GmbH & Co. KG.

[0083] CUROX CC-DC (or CCDFB-90) is a non-peroxidic CC initiator from United Initiators GmbH & Co. KG, 2,3-Dimethyl-2,3-diphenylbutane.

[0084] In order to be able to compare the burning rates of the various mixtures, 100 g of the preparation were ignited in each case and the amount of the substance still remaining was determined with respect to time. The procedure corresponds to BG regulation B4, Annex 4, version dated 1 Jan. 1997, Annex 4 for liquids. The procedure was adapted to solids. The results are shown in FIG. 1.

[0085] It was found that the burning rate decreases when BCHPC powder is mixed with an inert solid such as dicyclohexyl phthalate, fluorene, aluminium trihydroxide, polystyrene and glyceryl tribenzoate.

[0086] 1.2 Combination of BCHPC with Dicylohexyl Phthalate in Different Mixing Ratios

[0087] To analyse the influence of the quantity of desensitising agent used on the burning rate, combinations of BCHPC with dicyclohexyl phthalate in different mixing ratios were produced. The burning rate was analysed as described in Example 1.1. The mixtures tested were BCHPC: dicyclohexyl phthalate in a ratio of 5:1, 2:1 and 1:1 as well as pure BCHPC. It was found that with the addition of a larger quantity of desensitising agent, the burning rate also decreases further. The results are shown in FIG. 2.

[0088] 1.3 Combination of BCHPC with Organic Peroxide

[0089] To analyse the rate of burning of a mixture of BCHPC with one or more further organic peroxides, combinations of BCHPC with dilauroyl peroxide (LP) or dicetyl peroxydicarbonate (CEPC) were produced in various mixing ratios. In addition, combinations of BCHPC with dilauroyl peroxide and myristyl peroxydicarbonate (MYPC) in the ratio 1:1:1 or BCHPC with MYPC in the ratio 2:1 were examined. The analysis of the rate of burning was carried out as described in Example 1.1. The results are shown in FIGS. 3A and 3B.

[0090] For mixtures of BCHPC and LP, comparisons of mixing ratios of 5:1, 4:1, 3:1, 2:1, 1:1 and 1:2 were examined. The burning rate was lower in each case than observed for pure BCHPC. In the case of an excess of dilauroyl peroxide (BCHP: CUROX LP-S=1:2) the rate of burning is not so significantly reduced as in a ratio of 1:1, but the ignition of the mixture took significantly longer than with the other mixtures.

[0091] For combinations of BCHPC with dicetyl peroxydicarbonate, the mixing ratios 81.5:18.5, 2:1 and 1:2 were analysed.

[0092] It can be seen that in all cases the combustion of the mixtures compared to pure BCHPC is significantly delayed, although the BCHPC is combined with one or more further organic peroxides, due to which, further active oxygen is introduced into the preparation.

[0093] 2. Cure Rate of Various BCHPC Preparations

[0094] To analyse the cure rate of mixtures of BCHPC and various organic peroxides, a curing test was conducted in accordance with DIN16945. The following mixtures were analysed: [0095] BCHPC [0096] BCHPC-75-W [0097] BCHPC/CUROX LP-S(80%)-2:1 [0098] BCHPC/CEPC 65%-2:1 [0099] BCHPC/CEPC 65% (81.5:18.5) [0100] CEPC 65% [0101] CEPC [0102] BCHPC/CUROX LP-S/MYPC (1:1:1)

[0103] CEPC 65% is an approximately 65% water-moistened dicetyl peroxydicarbonate. It was found that with the various mixtures analysed, the cure rate compared with undiluted BCHPC decreases only slightly. In the case of the mixture of BCHPC and water-moistened CEPC powder, even an increase in the curing rate was observed. The results are shown in FIG. 4.